🎧 Prefer to listen? Part 1 of 2, about 26 minutes.
Covers what the FDA actually changed this summer, then the first five peptides: BPC-157, TB-500, thymosin alpha-1, thymulin, and pinealon. Part 2 picks up further down the page.

Peptide Therapy in 2026: What Changed, and What the Evidence Actually Shows
Start Here: What Is a Peptide, and Why Does the Category Barely Make Sense?
Three Categories: Approved, Compoundable, and Neither
What the July 2026 Vote Actually Did
How I Grade the Evidence Here
1. BPC-157: The Most Discussed, Least Proven Peptide in Medicine
2. TB-500 and Thymosin Beta-4: The Other Half of the “Wolverine Stack”
3. Thymosin Alpha-1: The Best-Evidenced Peptide Almost Nobody Talks About
4. Thymulin: The Peptide You Cannot Buy, and the Intervention You Can
5. Pinealon (EDR): A Tripeptide That Is Not From the Pineal Gland
6. Epithalon (Epitalon): Telomerase, Melatonin, and a 15-Year Study Worth Scrutinizing
7. GHK-Cu: The Copper Peptide, and the One Peptide on This List You Can Actually Get Today
8. Growth Hormone Secretagogues: Where Endocrinology Actually Has Something to Say
9. Peptides That Stimulate Testosterone in Men
10. Peptides in Women’s Reproductive and Sexual Health
Quick Reference: What You Can Actually Get in the US Right Now
Sourcing: The Risk That Never Makes It Onto the Sales Page
How I Would Approach This With a Patient
The Honest Summary
Schedule a Consultation in Fairfield, CT

Peptide Therapy in 2026: What Changed, and What the Evidence Actually Shows

In late July 2026, an FDA advisory committee did something it had never done before. It voted against the recommendation of the FDA’s own staff scientists and told the agency that several unapproved peptides, including BPC-157 and TB-500, should be allowed into compounding pharmacies.

As a board-certified endocrinologist practicing functional medicine in Fairfield, CT, I have watched peptide questions go from an occasional curiosity to one of the most common reasons people contact my practice. That vote is going to accelerate things considerably, and it is going to generate an enormous amount of misleading marketing along with it.

Written August 5, 2026. Everything in this article about what is legal, what is available, and where you can obtain it reflects the situation on that date and nothing after it. This field has changed several times in the past three years and will change again. Several decisions currently pending at the FDA are expected to land between now and early 2027. If you are reading this months later, treat the regulatory sections as a snapshot rather than current fact, and verify anything you plan to act on.

So I want to do something different with this article than what you will find on most peptide websites.

I am going to walk through ten peptides and peptide classes. For each one: how it works, what it is used for, how strong the human evidence actually is, dosing as it is actually used, side effects, contraindications, how long people stay on it, and the lab work I would want to see. Then, for each one, the question almost nobody answers clearly: can you actually get this legally in the United States right now, and from where?

Let me also say plainly what I do and do not do, because it matters for how you read this.

I have not prescribed peptides so far, but as new information unfolds, I am reconsidering my stance. First, do no harm is a core principle.

I prescribe insulin and GLP-1 medications, which are technically peptides but belong in a separate conversation. I do not stock, inject, or resell BPC-157, TB-500, GHK-Cu, or anything else on this list, and I take no margin on compounded products.

That is my position today, not a permanent one. The evidence in this field is moving, and so is the regulation. I expect to prescribe certain peptides in the near future as better data emerges, in specific situations: where there is a genuine clinical indication, where laboratory findings support the decision, and where the product itself is legitimate and available through a reputable pharmacy. All three, not one or two.

What I can do right now is help you navigate a confusing landscape without a stake in which direction you go. I have no financial reason to talk you into any of this. What I do have is twenty-five years of endocrinology and a reasonably firm view about which of these compounds rest on real data and which rest on enthusiasm.

Much of the framing here draws on the June 2026 Huberman Lab episode with Dr. Abud Bakri, an internal medicine physician with an unusually deep command of this literature. It was the most honest public discussion of peptides I have heard. I have added the endocrinology, the monitoring, the availability picture, and the regulatory verification.

This builds on my earlier guides to the 14 peptides of the 2026 HHS reclassification and to BPC-157 specifically. GLP-1 medications get their own separate discussion.

Start Here: What Is a Peptide, and Why Does the Category Barely Make Sense?

A peptide is a short chain of amino acids, the same building blocks that make up proteins. The dividing line is roughly size: chains under about 40 to 50 amino acids get called peptides, longer chains get called proteins. Insulin is a peptide. So is semaglutide. So is BPC-157.

Your body uses peptides as a signaling language. Cells talk to each other with them, the way they also talk with steroid hormones, neurotransmitters, and inflammatory messengers.

Here is the distinction Dr. Bakri drew that I think is the single most useful idea in this entire field.

Some peptides have a known receptor. Some do not.

Think of a receptor as a lock sitting on the surface of a cell, and the peptide as the key. Once you know which lock a peptide fits, you can predict a great deal: what it will do, what it will not do, roughly what dose is needed, and what side effects to expect. GLP-1 medications have a well-mapped lock, which is precisely why we can discuss them with confidence.

For BPC-157 and TB-500, nobody has found the lock. That does not mean these compounds do nothing. It means we are guessing at what they do based on what happened to rodents, rather than understanding why it happened.

That distinction runs through everything below.

Three Categories: Approved, Compoundable, and Neither

Most of the confusion in this field comes from squashing three very different things into the phrase “peptides are legal now.” Knowing which category a compound falls into tells you more than any marketing page will.

Approved. A company ran the trials, submitted the data, and the FDA cleared a specific product for a specific condition. You get pharmaceutical manufacturing, guaranteed purity, and a package insert. Very few peptides qualify.

Compoundable. A compounding pharmacy is a licensed pharmacy that makes a medication for one particular patient against one particular prescription. There are two kinds, and the distinction comes up repeatedly below. A 503A pharmacy compounds for an individual patient against an individual prescription. A 503B outsourcing facility produces larger batches for office stock under stricter manufacturing standards, closer to those of an actual drug manufacturer.

Neither can use just any ingredient. The FDA maintains lists of which bulk substances are permitted, published on FDA’s bulk drug substances page. Being on a list means a pharmacy may legally make it for you. It says nothing about whether it works.

Neither. No approval, no pharmacy pathway. In the United States these exist only as “research use only” chemicals sold online, labeled not for human consumption. This is where most of the peptide market actually lives, and where all of the quality problems are.

What the July 2026 Vote Actually Did

You have probably seen headlines suggesting peptides just became legal. Here is what really happened.

Back in September 2023, the FDA restricted roughly seventeen to nineteen peptides, which shut down US pharmacy production of BPC-157, TB-500, thymosin alpha-1 and others essentially overnight. In April 2026 most of those restrictions came off, though that put the compounds in limbo rather than making them available.

Then on July 23 and 24, 2026, an FDA advisory committee reviewed seven peptides and recommended six of them: BPC-157, TB-500, KPV, MOTS-c, Semax, and epitalon. Only emideltide (DSIP) was turned down. The individual vote margins are in the reference table further down.

Two things about that meeting are worth knowing.

The FDA’s own scientists had recommended against all seven. Agency staff reviewed each one beforehand and said no to every one, citing poor chemical characterization, almost no human effectiveness data, and unknown risk of the body mounting an immune reaction against the injected peptide. The committee overruled them six times in two days, which a panel like this had rarely if ever done before. One FDA reviewer asked out loud during the meeting, “What is BPC-157?” He was not being sarcastic. His point was that if you cannot agree on exactly what a substance is, you cannot judge whether one batch matches the next.

The panel had just been reshuffled. Eight new temporary members were added shortly before the meeting. On day one, all eight new appointees voted yes and the longer-serving members voted no. Several of the new members have professional ties to businesses that prescribe, produce, or promote peptides. HHS says everyone passed standard ethics review. Draw your own conclusion.

And here is the part the marketing leaves out

None of the six was approved, and none of the six became legally available.

I want to be precise about that sentence, because it is narrower than it first sounds and the difference matters.

The committee only advises. For anything to actually change, the FDA has to accept the recommendation and then go through formal rulemaking: a proposed rule, a public comment period, and a final rule. Legal analysts put realistic availability in 2027 at the earliest.

I checked rather than assumed. Empower Pharmacy, one of the largest and most rigorously accredited compounders in the country, updated its published list of available peptides on July 28, four days after the vote. Not one of the six was added. They legally could not add them, because a favorable committee vote does not put a substance on the FDA’s list. Only rulemaking does.

Two things that sentence does not mean.

It does not mean no peptides are available. Several are, right now, through legitimate compounding pharmacies with a prescription: sermorelin, gonadorelin, and non-injectable GHK-Cu among them. I go through each one below and I list them all in a table further down. That has been true for some time and the July vote did not change it either way.

And it certainly does not mean BPC-157 and TB-500 are hard to get. You can order either one online this afternoon. What you cannot do is obtain them from a licensed pharmacy that tested the product, verified its identity, and stands behind what is in the vial. The compounds are available. Reputable sourcing for them is not. That distinction is the entire subject of the sourcing section near the end of this article, and it is where people actually get hurt.

Gray-market sellers are already advertising the vote as though something changed. Nothing did.

If a clinic tells you peptides are “now FDA approved,” or that the six recommended peptides are available today, they are either uninformed or selling you something.

How I Grade the Evidence Here

I use three tiers, because putting a hepatitis B drug and a Soviet-era tripeptide in the same category does everyone a disservice.

Tier 1: Human randomized controlled trial evidence. Published, replicated, approved somewhere by a real regulatory agency.

Tier 2: Limited human data. Small trials, single center, single research group, or approved outside the US on a data package the FDA declined.

Tier 3: Preclinical only. Animal and cell culture work plus clinical anecdote. Most of the popular peptide market lives here.

None of the doses below are a prescription or a recommendation. For unapproved compounds, no dose has ever been validated in a human trial. I am reporting what is used so you understand the landscape.

Reminder on the availability notes below: each reflects August 5, 2026. Two FDA decisions are pending, on the six recommended peptides and separately on injectable GHK-Cu, and either could change several of these entries.

📞 Thinking about peptides? Get the endocrinology sorted first.

Peptides act on the thyroid, adrenal, gonadal, and metabolic axes at the same time. Most peptide clinics never check any of them. Call (203) 760-5544 to schedule a comprehensive hormone evaluation in Fairfield, CT.

1. BPC-157: The Most Discussed, Least Proven Peptide in Medicine

Evidence tier: 3, with two small Tier 2 human trials that were never fully published.

Where it came from

BPC-157 is a 15-amino-acid segment of “body protection compound,” a larger protein isolated from human gastric juice by a research group in Zagreb, Croatia, starting in 1991. Your body does not make BPC-157 itself. It makes the larger parent protein.

The backstory is genuinely interesting. Pavlov, of the famous dogs, also collected canine gastric juice and sold it as a remedy for indigestion. Separately, Hans Selye described what happens to a stressed animal: the adrenal glands enlarge, the stomach lining erodes, and the thymus shrinks. The Croatian group reasoned that if the gut lining protects itself under stress, there must be a protective compound in the gastric juice. BPC-157 is what they found.

How it works

No receptor for BPC-157 has yet been identified. That is not a footnote, it is the central scientific problem with this compound, and it is stated plainly in the professional pharmacy literature as recently as mid-2026.

Candidate interactions have been proposed, and the compound appears to act through several pathways simultaneously rather than through one target, which is part of why pinning down a receptor has proven so difficult. What the animal work shows is broad modulation of repair signaling:

It increases VEGF, a signal that tells the body to grow new blood vessels. Injured tissue needs blood supply to heal, so this is the proposed benefit. It is also the main theoretical worry, for reasons I come back to below.
It affects nitric oxide, which widens blood vessels and increases blood flow into an injured area.
It switches on the machinery cells use to crawl. Repair cells have to physically travel to the site of an injury, and this appears to speed that up.
It makes tendon cells more sensitive to growth hormone they are already exposed to, rather than adding more hormone.

The finding I find most striking involves steroids. Corticosteroids like prednisone shut wound healing down hard. In animals given both a steroid and BPC-157, healing continued anyway.

That points to something specific. BPC-157 appears to speed up repair rather than damp down inflammation, and those are genuinely different approaches. Anti-inflammatories work by turning the alarm off. This appears to work by sending the repair crew in faster. Whether that holds true in humans is an entirely separate question, and one nobody has answered.

What it is used for

The original target was the gut: ulcer protection, inflammatory bowel disease, reflux. The musculoskeletal use for tendon, ligament, and muscle injury came later and is what drove the popular interest.

There is also a strange and underappreciated neurological literature. In rodents, BPC-157 blunted intoxication, prevented alcohol withdrawal symptoms, and modulated dopamine signaling in both directions. Patients report a version of this: a recurring complaint is that oral BPC-157 dulls the effect of their stimulant medication.

The proposed explanation is that BPC-157 acts on the gut-brain axis, the two-way signaling highway between the intestinal lining and the brain, and that its effect is homeostatic. It keeps the system from swinging too far in either direction. In the rodent work the animals could not get very drunk, and they also could not withdraw. Interesting, and completely unstudied in humans.

Efficacy: what we actually know

In humans, close to nothing, and I want to be precise about how little.

The most rigorous accounting is the 2025 systematic review by Vasireddi and colleagues in HSS Journal, out of Case Western and University Hospitals Cleveland. They screened 544 articles published between 1993 and 2024 and included 36. Thirty-five were preclinical. One was clinical.

That single clinical study was an uncontrolled chart review of 16 patients with knee pain, with outcomes collected by telephone survey. No control group, no blinding, single center. Counting more generously across the literature, you get roughly three uncontrolled pilot studies with about 30 participants total.

A phase 1 study registered in 2015 was cancelled. No public explanation was given, and as of 2026 nothing is actively recruiting on ClinicalTrials.gov.

There is also a Croatian line of work on rectal BPC-157 in ulcerative colitis, at doses far higher than anything used recreationally. I have seen it referenced repeatedly, but I have not been able to locate full published results in the peer-reviewed literature, and it did not surface in the systematic review’s inclusion set. Treat it as unverified until someone produces the paper.

Two further limitations matter as much as the sample sizes.

Nearly all of the animal literature comes from one research group, centered on Predrag Sikirić at the University of Zagreb. The 2025 Vasireddi review documented that concentration explicitly. Independent replication by unaffiliated laboratories is limited, though it exists: the VEGFR2 work by Hsieh in 2017 and the FAK-paxillin tendon studies by Chang in 2011 and 2014 are the notable examples.

The pharmacokinetics are essentially uncharacterized in humans. Plasma half-life is estimated at under 30 minutes, and there are no published human pharmacokinetic data at all. In the gut-administration work, BPC-157 was not detectable in the bloodstream after oral or rectal dosing. Either it is degraded immediately or it acts locally and never travels systemically. Nobody has established which.

Sit with what that means. A very large number of people, in a gray market estimated in the billions of dollars annually, are injecting a compound whose receptor has not been identified, whose distribution in the human body has never been measured, and whose entire human efficacy record is one uncontrolled chart review of sixteen people.

Dosing as actually used

For gut-focused use, which is closest to the original research:

Oral: 250 to 500 mcg once or twice daily for four to eight weeks. Oral makes mechanistic sense here because the target tissue is the gut lining itself, so systemic absorption may not even be required.

You will see “take on an empty stomach” or “away from food” attached to oral BPC-157 nearly everywhere. I am not going to repeat that instruction, because I cannot defend it.

The usual reason for dosing a peptide on an empty stomach is to protect it from stomach acid and digestive enzymes. But BPC-157’s entire origin story is that it was isolated from gastric juice and is said to be stable there. If that is true, the rationale does not apply to this particular compound. The advice appears to have been carried over from other peptides without anyone checking whether it fits this one.

There is no human pharmacokinetic data for oral BPC-157. None at all. So no timing instruction is defensible, including “with food,” and I would rather say that plainly than invent a number.

Often paired with the rest of a gut protocol: removing the irritant, correcting deficiencies, and addressing the actual driver, whether that is H. pylori, small intestinal bacterial overgrowth, NSAID use, or untreated celiac disease.

For musculoskeletal use:

Injectable: 150 to 375 mcg subcutaneously once or twice daily, either near the injury or systemically, in cycles of four to twelve weeks.

Worth noting: Dr. Bakri has argued publicly that these microgram doses were reverse-engineered from what fits in a vial on a peptide website rather than derived from any human data, and that the true effective human dose is likely far higher. He may well be right, which is another way of saying nobody knows.

Side effects

In animals, none reported, even at doses many hundreds of times higher than typical human use. The LD50, the dose that kills half of test animals and a standard safety benchmark for every drug you have ever taken, does not appear anywhere in the published literature for BPC-157. I could not find one. That absence is itself an obstacle to approval, and it is worth understanding that “no reported toxicity” and “toxicity has been ruled out” are not the same statement. Fewer than 30 humans have been studied in total. Rare adverse events would not show up in a sample that size.

The following are reported by patients and clinicians rather than captured in any adverse event registry. Treat them as signals to watch for, not as established rates:

Blunted response to stimulant medications, low mood, and anhedonia (loss of pleasure)
GI upset with oral forms
Worsening of angiomas, the small red vascular spots on the skin, and of bruising. Mechanistically consistent with a compound that promotes blood vessel growth, which is why I mention it, but the connection is inferred rather than demonstrated.
Injection site irritation and fatigue
Dizziness and cardiovascular effects, proposed to run through the nitric oxide and VEGF pathways

The cancer question, which is genuinely contested

I want to handle this carefully, because it is the risk that matters most and because I have seen it stated with more confidence than the evidence supports, in both directions.

The concern is theoretical, not demonstrated. A tumor needs a blood supply to grow, BPC-157 promotes blood vessel formation, and an undetected tumor is the scenario you would least want to feed. The professional literature describes this as a theoretical oncologic liability. There is no human case series, no cohort study, and no animal carcinogenicity data establishing that BPC-157 causes or accelerates cancer. Anyone telling you it does is overstating.

And it is actively disputed in print. A 2025 literature and patent review by Józwiak and colleagues in Pharmaceuticals raised exactly these angiogenesis and carcinoma concerns. Sikirić’s group published a formal rebuttal in the same journal arguing that the criticisms do not hold, that BPC-157 behaves differently from standard angiogenic peptides, and that it operates outside the framework of Folkman’s classical angiogenesis model, which is the model that predicts the tumor risk in the first place. They also point out that BPC-157 reduces VEGF in some tumor models rather than raising it.

I am not in a position to adjudicate that dispute, and neither is anyone else right now, because the human data to settle it does not exist. What I can tell you is that the people who discovered the compound and the people reviewing it independently disagree in the peer-reviewed literature about whether the cancer concern is real.

What I would do with that uncertainty. I would want age-appropriate and risk-appropriate cancer screening completed before starting, not after, and I would not use it in someone with active malignancy or a recent cancer history. Not because the risk is proven, but because the cost of that precaution is a screening colonoscopy or a mammogram you were due for anyway, and the cost of being wrong in the other direction is not recoverable. That is a judgment about asymmetry, not a claim about evidence, and I would rather be explicit about which one I am making.

Other cautions

Pregnancy and breastfeeding. No data, standard precaution.
Untreated proliferative diabetic retinopathy, which is itself a disease of abnormal blood vessel growth in the eye. Same mechanistic logic, same theoretical status.
Competitive athletes. This one is not theoretical at all. BPC-157 is prohibited at all times under the World Anti-Doping Agency code, and athletes have been sanctioned on self-report alone, with no positive test.

Duration

Cycled, not continuous. Four to eight weeks with a defined endpoint, then stop and reassess. There is no data supporting chronic use and no data on what years of angiogenic stimulation do.

Monitoring I would want

There is no validated blood marker for BPC-157. What I would want documented:

Baseline CBC, comprehensive metabolic panel, and hs-CRP
Age-appropriate and risk-appropriate cancer screening completed before starting, not after
PSA in men over 40
A written functional endpoint with a stop date. If the shoulder is not better at six weeks, it is not going to be.

Availability in the US right now

Bucket 3, moving toward Bucket 2. BPC-157 is not FDA approved for anything. It came off Category 2 in April 2026 and received a favorable advisory committee vote in July 2026, but it has not been added to the 503A bulks list, and rulemaking has not begun.

It is not currently on the menu at major 503A pharmacies. Empower Pharmacy, one of the largest and most rigorous compounders in the country, does not list BPC-157 among the peptides it can prepare today.

If someone is selling you BPC-157 right now, it is almost certainly a research-chemical product, not a compounded prescription.

2. TB-500 and Thymosin Beta-4: The Other Half of the “Wolverine Stack”

Evidence tier: 3.

How it works

Thymosin beta-4 is a 43-amino-acid peptide that manages a protein called actin. Actin is the internal scaffolding a cell uses to change shape and crawl along, a bit like a tent frame the cell can assemble and take apart at will. By controlling how that scaffolding gets built, thymosin beta-4 controls how easily cells can move.

That is the whole rationale. Immune cells and fibroblasts have to physically travel to reach injured tissue, and this peptide speeds that up. It also promotes new blood vessel formation and dials down inflammatory signaling.

TB-500 is a synthetic fragment based on the active region of thymosin beta-4, not the full molecule. What is actually in any given vial varies between suppliers, and inadequate chemical characterization was one of the FDA’s explicit objections at the July hearing.

Indications and efficacy

The preclinical work is legitimately interesting: faster skin wound closure, less cardiac scarring after a heart attack, corneal healing after chemical burn.

Full-length thymosin beta-4 has been through human eye trials for neurotrophic keratopathy and dry eye. TB-500 itself has essentially no controlled human data for musculoskeletal use.

Its most established real-world use is horse racing, where it has been a doping agent for years.

Dosing as used

2 to 2.5 mg subcutaneously twice weekly for a four to six week loading phase, then reduced frequency for maintenance. Commonly stacked with BPC-157 under the nickname “Wolverine stack,” which somebody invented on the internet and which is not a protocol.

Side effects, contraindications, duration, monitoring

Reported side effects are mild: lethargy, injection site reaction, transient head rush after injection.

Contraindications mirror BPC-157, with cancer history the principal one given the pro-angiogenic and pro-migratory activity. TB-500 is explicitly named on the 2026 WADA Prohibited List under growth factors, with a default four-year sanction.

Duration is loading plus maintenance, generally under twelve weeks. Monitoring is the same framework as BPC-157, with cancer screening current before starting.

Availability in the US right now

Bucket 3, moving toward Bucket 2. Same trajectory as BPC-157: off Category 2 in April 2026, favorable advisory vote in July 2026, not yet on the 503A bulks list, not offered by major compounders today. Research-chemical channels only at present.

3. Thymosin Alpha-1: The Best-Evidenced Peptide Almost Nobody Talks About

Evidence tier: 1 outside the United States. Unapproved inside it.

This peptide has the strongest human data on this entire list and gets a fraction of the attention BPC-157 gets. That tells you a great deal about how this market works.

Background biology: the thymus

The thymus is a gland sitting just behind the breastbone, above the heart. It is where T cells, the immune cells that recognize and kill infected or cancerous cells, go to be trained. That training is what keeps them from attacking your own tissue.

The thymus is enormous in infancy and starts shrinking at puberty. This is called thymic involution, and it is driven largely by androgens, estrogens, progestins, and cortisol. In other words, the hormones everyone wants more of are the ones that shrink the thymus.

By your thirties and forties the thymus is mostly fat with small islands of functional tissue. Output of naive T cells falls dramatically, and those cells live roughly ten to fifteen years. That timeline lines up uncomfortably well with when cancer, autoimmune disease, and infection risk start climbing.

This is not fringe biology. A 2026 paper in Nature found that people with higher thymic scores on imaging had lower mortality across cardiovascular disease, cancer, and other endpoints. There is also good New England Journal data showing that removing residual thymic tissue during cardiac surgery is associated with higher rates of cancer and autoimmune disease afterward.

I find this genuinely under-discussed in mainstream endocrinology, and I say that as someone who spends his career in mainstream endocrinology.

How thymosin alpha-1 works

Thymosin alpha-1 is a 28-amino-acid peptide from the thymus, isolated by Allan Goldstein’s laboratory in the 1970s. It works through sensors called Toll-like receptors, which sit on immune cells and act as the body’s pattern detectors. They are the part of the system that recognizes something as foreign and decides to respond.

What follows is better T cell development, more of the main T cell subtypes, stronger natural killer cell activity, and better presentation of threats to the immune system.

The important word is restores. This is not a compound that revs the immune system up indiscriminately. It appears to bring a depleted system back toward normal function, which is a meaningfully different thing and part of why its safety record is as good as it is.

Indications and efficacy

Approved as thymalfasin (brand name Zadaxin) in more than 35 countries for chronic hepatitis B, chronic hepatitis C, and as an adjunct in cancer care. The pivotal hepatitis B randomized trial reported complete virological response in about 41 percent of treated patients versus about 9 percent of untreated controls.

It has never been FDA approved in the United States. SciClone advanced it through US phase 3 hepatitis trials in the 1990s and 2000s without securing approval. It does hold FDA orphan drug designations for malignant melanoma, hepatocellular carcinoma, chronic active hepatitis B, and DiGeorge anomaly. Orphan designation is an incentive for developing drugs for rare diseases. It is not approval.

Off-label interest centers on immune support, recurrent infection, post-viral syndromes, and post-COVID recovery. Be clear with yourself that this use is not supported by the hepatitis data. The sepsis and general infectious disease literature has been unimpressive.

Dosing

The validated regimen is the hepatitis B protocol: 1.6 mg subcutaneously twice weekly, spaced three to four days apart, for six to twelve months. Adults under 40 kg use 40 mcg/kg twice weekly.

Wellness protocols typically run two to three months on, one month off, at similar doses.

Side effects and contraindications

Four decades of low adverse event data across multiple indications. Injection site reactions dominate. By any reasonable standard this is a well-tolerated compound, which is exactly why the regulatory situation is frustrating.

Contraindications:

Organ transplant recipients on immunosuppression. Enhancing T cell function is precisely wrong here.
Active autoimmune flare. This is theoretical rather than documented, but I would not use it in poorly controlled Graves’ disease or an active Hashimoto’s flare. See my post on Graves’ disease for why an already overactive immune response is not something to amplify.
Pregnancy and breastfeeding

Duration and monitoring I would want

Approved protocols run 26 to 52 weeks. Off-label immune use is typically cycled.

CBC with differential. This is the cheap, badly underused test in this whole discussion. It costs almost nothing, and most patients have already had one sitting in their chart.

Two numbers on it deserve attention. Absolute lymphocyte count: a young, healthy person typically runs 1,500 to 3,000. Falling below roughly 1,000 tracks with worse outcomes across a striking range of diseases.

Lymphocyte-to-monocyte ratio, which you get by dividing one by the other. Most healthy adults land somewhere around 3 to 5. I want to be careful with that number: it is a derived value rather than a standardized clinical test, there is no universal reference range, and it shifts with the laboratory and the instrument. Research cutoffs vary by the disease being studied, generally clustering between about 3.0 and 4.7. Treat it as a trend you follow in one person over time rather than a pass-fail threshold. The direction it moves matters more than whether it clears a particular line.
CD4/CD8 flow cytometry where clinically warranted
Baseline autoimmune panel in anyone with a personal or family autoimmune history

Availability in the US right now

Bucket 3. Not FDA approved. It went to Category 2 in 2023 and its compounding status has changed repeatedly since, with sources currently in genuine conflict about where it stands. It is not on Empower’s current list of peptides available to prescribe.

Zadaxin is a real pharmaceutical product, but it is not marketed in the United States. This is, to me, the most frustrating entry on the list: the best human evidence, and the least legitimate access.

4. Thymulin: The Peptide You Cannot Buy, and the Intervention You Can

Evidence tier: 3 in humans. The actionable part is Tier 1.

Thymulin is a nine-amino-acid peptide identified by a French group as the principal thymic hormone. It is constantly confused with thymalin, the Russian polypeptide thymic extract. They are different compounds, and most peptide vendors get this wrong.

Why this one is clinically useful even though you cannot get it

Thymulin is zinc dependent. The peptide is biologically inactive without a zinc ion bound inside it. Biology does this repeatedly: hemoglobin needs iron, GHK needs copper, thymulin needs zinc.

Here is the part that changes practice. Falling thymulin activity is the earliest detectable marker of zinc depletion. It drops before serum zinc or red blood cell zinc move at all. Serum zinc is a notoriously poor test, and this is part of the reason.

In animal studies, thymulin also appears to make target organs more responsive to signals from the pituitary. Given alongside hCG, it produced more testosterone than hCG did on its own. That hints at a connection between the thymus and the reproductive system that is essentially unexplored in humans.

The honest translation

There is no commercially available thymulin product anywhere, no human dosing protocol, and no trial data. Its half-life is extremely short.

So the intervention is not the peptide. It is zinc status. Adequate zinc is required for your own thymulin to work, and zinc deficiency is common in exactly the patients who come in asking about immune peptides.

Monitoring I would want: RBC zinc rather than serum zinc, copper (sustained zinc supplementation above roughly 40 mg daily induces copper deficiency), and CBC with differential.

Availability in the US right now

Not available in any legitimate channel. No approved product anywhere, no human protocol, no trial data.

It has, however, been nominated for compounding. Thymulin acetate appears in FDA’s Category 3, the designation for substances nominated without adequate supporting information. That is the weakest of the three categories, and it is a reasonable place for a compound with no human dosing data and an extremely short half-life.

Zinc, by contrast, is at the grocery store.

5. Pinealon (EDR): A Tripeptide That Is Not From the Pineal Gland

Evidence tier: 3, and the human data is Soviet era.

What it actually is

Pinealon is the tripeptide Glu-Asp-Arg, often abbreviated EDR. It is one of roughly forty short peptides characterized by Vladimir Khavinson in a Soviet research program aimed at protecting submariners, pilots, and cosmonauts, populations that came back from deployment looking and testing years older than they went in.

Despite the name, it is isolated from cortical brain extract, not from the pineal gland. The naming in this field is genuinely terrible, and Huberman suggested on the podcast that we simply call it EDR instead. I agree.

How it works

Khavinson’s proposal is unusual. He argued that peptides this short can slip directly into the groove of the DNA double helix and expose the stretches that control whether a gene gets read or stays silent. Rather than docking at a lock on the cell surface, in other words, they would work inside the nucleus, changing which genes are switched on.

The pathways he reported include PPAR-alpha and PPAR-gamma, which are master switches for how the body handles fat and sugar; superoxide dismutase, your main internal antioxidant enzyme; and a couple of others. The overall claim is that brain cells end up in better metabolic shape.

I would note that this mechanism is his group’s model, not established consensus.

There is no known receptor. Being only three amino acids long, it is orally absorbed through peptide transporters and probably crosses the blood-brain barrier.

What it is used for

It was developed as an anti-stress and cognitive performance compound and is sold over the counter in several post-Soviet countries. Khavinson studied it in athletes: the treated group maintained cognitive performance after training to exhaustion where the placebo group did not.

The effect that gets discussed most, a large increase in REM sleep, appears nowhere in Khavinson’s published work. Sleep tracking did not exist in 1970s Soviet research. It is a modern observation from consumer wearables, which is worth exactly as much as that sounds.

Dosing

Khavinson’s original protocols used 100 to 200 mcg. Contemporary oral use runs considerably higher, roughly 0.5 to 3 mg. Injectable forms are used and appear to distribute systemically.

Timing matters. Taken at night it can fragment slow-wave sleep. The original design was for morning or pre-workout use.

Side effects and contraindications

Hypoglycemia. PPAR-alpha and PPAR-gamma activation lowers blood glucose, and clinicians report drops in HbA1c. In a patient on insulin or a sulfonylurea, this is an actual drug interaction, not a theoretical one. This is the risk I would flag hardest for my diabetic patients.
Vivid or disturbing dreams, sometimes markedly so
Sleep architecture disruption at higher evening doses

Contraindicated in pregnancy, and use caution in anyone at risk of hypoglycemia.

Duration and monitoring I would want

The Khavinson model is deliberately intermittent: short courses, once or twice a year, on the theory that the benefit accrues and persists after you stop. That is the opposite of the monthly subscription model most peptide clinics run on, and it is worth noticing who benefits from which framing.

Monitoring: fasting glucose and HbA1c, and continuous glucose monitoring in anyone on glucose-lowering medication.

Availability in the US right now

Bucket 3. No FDA approval, no compounding pathway, not on the July 2026 review docket. Available over the counter in Russia and several neighboring countries. In the US it is a research chemical only.

🎧 Part 2 of 2, about 26 minutes.
The remaining five: epithalon, GHK-Cu, growth hormone secretagogues, testosterone peptides for men, and peptides in women’s reproductive and sexual health, then how the whole picture fits together. Part 1 is at the top of the page.

6. Epithalon (Epitalon): Telomerase, Melatonin, and a 15-Year Study Worth Scrutinizing

Evidence tier: 3, with Tier 2 Russian human data of contested quality.

How it works

Epithalon is the four-amino-acid peptide Ala-Glu-Asp-Gly, isolated from the pineal gland. This is the one in the pair that is actually named correctly.

Reported actions:

It activates telomerase in human cells grown in a dish. Telomeres are protective caps on the ends of your chromosomes, often compared to the plastic tips on shoelaces. They get shorter every time a cell divides, and when they run down far enough the cell stops dividing. Telomerase is the enzyme that rebuilds them.

A word about telomeres and lifespan, because this is where the marketing gets ahead of the science. You will read that longer telomeres mean a longer life. The evidence does not support that, and I checked specifically before writing this section.

The strongest data comes from Mendelian randomization studies, which use inherited genetic variants to get at cause rather than mere correlation. The largest, covering 261,000 participants, found that genetically longer telomeres were associated with increased cancer risk and modestly lower coronary heart disease risk, with no association at all to parental lifespan, centenarian status in parents, cognitive function, grip strength, or frailty. Other work using the same method has linked longer telomeres to higher risk of lung adenocarcinoma, glioma, and soft tissue sarcoma. The authors of the large study concluded, in their own words, that telomere lengthening may offer little gain in later-life health while raising cancer risk.

Short telomeres do associate with age-related disease. That much is solid. But “longer is better” does not follow, and the reason is not mysterious: unlimited cell division is precisely what a cancer cell does. Telomerase reactivation is one of the defining features of malignancy.

So when a compound is marketed on its ability to lengthen telomeres, that is a mechanism claim, not a benefit claim, and the two are not the same thing.
Restoration of melatonin production in aged animals. Given to young monkeys it did nothing. Given to old monkeys with declining melatonin, it restored output. That pattern suggests a restorative rather than stimulatory mechanism, which is interesting.
Normalization of clock gene expression in peripheral tissue, with a more appropriate morning cortisol rise.

The pineal gland angle matters more than it gets credit for. Melatonin production falls steeply from puberty onward, and circadian disruption sits underneath a great deal of metabolic and hormonal dysfunction I see clinically.

The longevity data

Khavinson and Anisimov ran a fifteen-year study in nursing home residents using Epithalamin (whole pineal extract) alone or combined with Thymalin (thymic extract), given as brief courses of roughly ten to twenty days per year.

They reported significantly reduced mortality from cardiovascular disease, infection, and cancer.

Read that with the skepticism it deserves. Single research group, Soviet-era methodology, minimal independent replication. If it were reproduced in a Western cohort it would be among the most important longevity findings on record. It has not been.

Dosing

Two wildly divergent conventions exist: Khavinson’s original 100 mcg range, and contemporary Western protocols of 5 to 10 mg daily for 10 to 20 days, one or two courses per year. That is a fifty to hundredfold difference in dose for the same compound, which tells you how little consensus there is.

Side effects and contraindications

No consistent adverse effect signal in the Russian literature, with the caveat that the safety monitoring was not rigorous by modern standards.

The contraindication that matters is cancer. Telomerase reactivation is one of the defining features of malignant cells: it is how a tumor achieves unlimited division. A compound proposed to activate telomerase is mechanistically the wrong thing to give someone with active or recently treated cancer. I would want cancer screening current before anyone considered this, and I would not use it at all in a cancer survivor.

Also contraindicated in pregnancy.

Duration and monitoring I would want

Intermittent courses by design. No validated biomarker exists. Melatonin rhythm assessment and morning cortisol are the most defensible surrogates.

Availability in the US right now

Bucket 3. Approved in Russia, not in the US. Removed from Category 2 in April 2026, and on July 24, 2026 the advisory committee voted 7 to 4 with one abstention to recommend adding it to the 503A bulks list.

Notably, several committee members argued that safety decisions about epitalon should come down to a conversation between a doctor and a patient rather than a regulatory threshold. I have some sympathy for that position and also some concern about it, given that the compound is proposed to activate telomerase and the human data comes from one research group.

None of that changes availability today. Epitalon is not on the 503A bulks list, rulemaking has not started, and no major compounder offers it. Research-chemical channels only.

7. GHK-Cu: The Copper Peptide, and the One Peptide on This List You Can Actually Get Today

Evidence tier: 2 for topical cosmetic use. Tier 3 for everything else.

How it works

GHK-Cu is the tripeptide glycine-histidine-lysine bound to a copper ion. It occurs naturally within type I collagen fibers throughout skin, hair, and connective tissue. Loren Pickart identified it in the 1970s.

Blood levels run around 200 ng/mL at age 20 and fall to roughly 80 ng/mL by 60. That is one of the cleaner age-related declines in this entire field.

What it does is more interesting than “builds collagen.” It increases collagen production and controlled collagen breakdown at the same time, along with the natural brakes that keep the breakdown from running away.

That two-way action is the whole point. Renovating a house requires demolition as well as construction, and skin works the same way. Build without removing, and you get disorganized, scar-like tissue rather than good tissue. This is why GHK-Cu behaves differently from a compound that only pushes in one direction.

Indications and efficacy

Topical skin: reasonable human data. Trials have compared it favorably against vitamin C and retinol preparations for photoaging endpoints, with additional literature on repair after UV damage and some evidence of synergy with red light therapy. The consensus among people who work with it is to use it alongside a real skincare routine, not instead of one.

Hair: weak. One study was unimpressive. It is not a minoxidil replacement. As an adjunct alongside standard therapy, reasonable.

Injectable: no human data at all. A Chinese group is investigating lung regeneration, given how much connective tissue sits between the alveoli, but that is preclinical.

Dosing

Topical: 0.1 to 0.5 percent, roughly 1 to 5 mg/mL, in a properly formulated vehicle. Formulation matters enormously here. Many research-chemical topicals are poorly stabilized, and a real GHK-Cu preparation should be blue, which comes from the copper. Blue does not prove the complex is intact, but colorless argues strongly against it.

Two practical points. Do not layer it directly with L-ascorbic acid, which destabilizes the copper complex. And do not inject GHK-Cu into your face. Non-experts injecting facial tissue is how people end up with skin necrosis or, rarely, vision loss from vascular occlusion. I say this to patients regularly and I will say it here.

Side effects, contraindications, monitoring

Topical: irritation, contact dermatitis, transient blue staining.

Contraindications: Wilson’s disease or any copper handling disorder is absolute for systemic use. Use caution with concurrent oral copper supplementation.

Monitoring: none needed for topical use. For any systemic use, serum copper and ceruloplasmin.

Availability in the US right now

Bucket 2 for topical. Bucket 3 for injectable. This is the important distinction and almost nobody states it correctly.

On FDA’s 503A category list as updated May 14, 2026, the Category 1 entry reads, in full, “GHK-Cu (except for injectable routes of administration).” The route restriction is written into the entry itself, not appended as a footnote.

So: non-injectable GHK-Cu has a compounding pathway. Topical preparations can be legally compounded today with a prescription, and Empower Pharmacy currently offers a GHK-Cu Facial Serum and a GHK-Cu Scalp Solution through its 503A pharmacy. Other reputable compounders offer similar preparations.

Injectable GHK-Cu is excluded, and FDA has said it intends to consult the advisory committee before the end of February 2027 about whether GHK-Cu belongs on the 503A bulks list at all. Until then, injectable is not legally compoundable.

There are also legitimate cosmetic-grade GHK-Cu products sold as skincare, which have existed for thirty years and require no prescription. Quality varies enormously.

8. Growth Hormone Secretagogues: Where Endocrinology Actually Has Something to Say

Evidence tier: 1 for tesamorelin. Tier 3 for the anti-aging use case.

This is the class where my training is most relevant, and where I most often disagree with how these are prescribed elsewhere.

The two mechanisms people constantly conflate

A secretagogue is anything that makes a gland secrete more of its own hormone. These do not supply growth hormone. They tell your pituitary to release more of yours.

GHRH analogs (sermorelin, CJC-1295, tesamorelin) act at the growth hormone releasing hormone receptor. They amplify your existing pulses and leave the natural feedback loop intact, so the system can still shut itself off.

Ghrelin receptor agonists, often called GHRPs (ipamorelin, GHRP-2, GHRP-6, hexarelin, and the oral non-peptide MK-677), act at a different receptor called GHS-R1a. They produce a larger release but with less specificity, spilling into prolactin, cortisol, and appetite pathways.

Ipamorelin is the most receptor-selective of the GHRPs. It produces a clean growth hormone pulse without meaningfully raising cortisol or prolactin, which is exactly why it became the favorite in this category. MK-677 is at the opposite end: it drives growth hormone continuously rather than in pulses, which is the opposite of normal physiology. Growth hormone is normally released in a large burst during the first ninety minutes of deep sleep.

The question underneath all of this

Growth hormone output declines from roughly the third decade, a phenomenon sometimes called somatopause, by analogy with menopause and andropause.

The case for replacing it: IGF-1 (insulin-like growth factor 1, the downstream hormone that carries out most of growth hormone’s effects) contributes to skin quality, sleep depth, lean mass, joint integrity, and, relevant to the thymus discussion above, thymic regeneration. Greg Fahy’s TRIIM trial used growth hormone with metformin and DHEA and documented increased thymic volume on imaging with improved CD4/CD8 ratios.

The case against is substantial and does not get airtime in wellness marketing. Reduced growth hormone and IGF-1 signaling is one of the most reproducible longevity interventions in animal models. Within dog breeds, higher IGF-1 tracks with shorter lifespan: the Great Dane dies young, the Chihuahua does not. Growth hormone excess is clearly unfavorable cardiometabolically.

Biologists have a name for this pattern: a trait that helps you early in life and costs you later. Growth signals build a strong body in your twenties and may accelerate wear and tear across decades. Both halves can be true simultaneously.

Anyone who tells you this question is settled has not read the literature.

Regulatory status and what each one is

Tesamorelin (Egrifta) is FDA approved, dosed at 1.4 to 2 mg subcutaneously daily, for HIV-associated lipodystrophy, based on two phase 3 trials showing roughly 15 to 18 percent reductions in visceral fat. That is real Tier 1 evidence, for that population.

Sermorelin was FDA approved as Geref and withdrawn from the market by its manufacturer for commercial reasons, not safety. That prior approval gives it stronger legal standing than peptides that were never approved, which is precisely why it remains compoundable today.

CJC-1295 and ipamorelin have no FDA approval and no controlled human efficacy data for anti-aging or body composition. CJC-1295 has limited phase 1 human data. Ipamorelin’s published human data is thinner still.

MK-677 (ibutamoren) has never been approved anywhere and is not technically a peptide at all.

Dosing as used

Tesamorelin: 1.4 to 2 mg subcutaneously daily at bedtime (the approved regimen)
Sermorelin: 200 to 500 mcg subcutaneously nightly
CJC-1295 without DAC plus ipamorelin: commonly 100 to 300 mcg of each at bedtime, five days on and two off
MK-677: 10 to 25 mg orally at night

All of these require an empty stomach. Food triggers somatostatin release, and somatostatin is the body’s brake on growth hormone. Eat within a couple of hours of dosing and you have largely wasted the dose.

Side effects: the part most clinics skip past

Blood sugar is the dominant one, and this deserves a precise answer rather than a slogan.

Growth hormone is often described flatly as diabetogenic, meaning diabetes-producing. That is an overstatement, and as an endocrinologist I want to correct it rather than repeat it.

At true replacement doses, in adults with genuine growth hormone deficiency, growth hormone is not diabetogenic. Properly dosed replacement in a properly diagnosed patient restores a normal hormonal state. It generally improves body composition and does not push people toward diabetes.

The problem is what happens above that range. In supraphysiologic doses, meaning more than the body would ever produce on its own, growth hormone raises blood sugar and drives insulin resistance. That effect is real and well described.

So the risk is not the hormone. It is the dose.

And in practice, the dose is exactly where this goes wrong. The demand for these compounds is enormous, and a great many prescribers are willing to meet it without much scrutiny. Combination protocols pushing IGF-1 toward the upper end or beyond are common, and cycles get extended indefinitely because a monthly prescription is a monthly revenue line. The result is that in many cases, probably most, growth hormone stimulating peptides used for body composition or anti-aging do end up nudging blood sugar upward.

That is a statement about how these drugs are actually prescribed, not about the hormone itself. Both things are true at once, and conflating them is how the internet ended up with a bad answer.

Also:

Fluid retention, swelling, carpal tunnel syndrome, and joint pain
Increased appetite, pronounced with MK-677 and the GHRPs, minimal with tesamorelin
Prolactin and cortisol elevation with the less selective GHRPs. Everything in the pituitary sits in close quarters, and drugs that poke at it rarely hit one target cleanly.
Prostate effects. Huberman described a sharp PSA rise on sermorelin that resolved after stopping. The prostate enlarges with age under androgens, estrogen, and plausibly growth hormone.
Thyroid effects. Growth hormone accelerates conversion of T4 to T3, which can unmask marginal hypothyroidism or destabilize someone already on thyroid medication.
MK-677 specifically: fluid retention severe enough that a trial in elderly hip fracture patients showed a congestive heart failure signal.

Combination GHRH plus GHRP protocols can push IGF-1 into the 380 to 390 ng/mL range. That is a pubertal level in a fifty-year-old, and I would not consider it a target.

Contraindications

Active cancer. I hold this one firmly.
Uncontrolled diabetes and proliferative diabetic retinopathy
Symptomatic untreated benign prostatic hyperplasia
Untreated obstructive sleep apnea
Pregnancy and breastfeeding
Competitive athletes. All growth hormone secretagogues, including ipamorelin, CJC-1295, sermorelin, tesamorelin, and MK-677, are explicitly prohibited under WADA category S2.2.

Duration

If used at all, cyclically. Nothing in endocrine physiology runs at fixed output year round. A defined eight to twelve week course with testing before and after is defensible. Indefinite nightly use is not, and indefinite is what most clinics sell.

Monitoring I would want, and would not compromise on

IGF-1 before and during, targeting mid-normal for age rather than supraphysiologic. Anyone prescribing a secretagogue without checking IGF-1 is not practicing endocrinology.
Fasting glucose, fasting insulin, and HbA1c at baseline, six weeks, and twelve weeks
Full thyroid panel, for the T4 to T3 conversion issue above. Relevant to everyone I see for thyroid care.
PSA in men over 40, before and during
Blood pressure and assessment for swelling
Age-appropriate cancer screening current before starting

Availability in the US right now, including the ipamorelin question

This is where the answer surprises people, so let me be specific.

Tesamorelin (Egrifta): Bucket 1. FDA approved and commercially available, but only for HIV-associated lipodystrophy. Using it for body composition in a healthy patient is off-label prescribing of an approved drug, which is legal but is not what the approval covers, and it is expensive.

Sermorelin: Bucket 2, and available today. This is the growth hormone secretagogue you can actually get through a legitimate US compounding pharmacy right now. Empower currently lists both a sermorelin acetate injection and a sermorelin acetate orally disintegrating tablet among the peptides it can prepare with a prescription. Its prior FDA approval as Geref is what preserves that pathway.

Ipamorelin: not available, and its status is stranger than “restricted.” Ipamorelin is the most receptor-selective GHRP and I understand why it is the one people ask about.

I went and read FDA’s actual 503A category list, updated May 14, 2026, rather than relying on the secondary sources, which conflict wildly on this point. Here is what it shows: ipamorelin does not appear in Category 1, Category 2, or Category 3. It is on none of the three lists.

That is not the same as being banned, and it is not the same as being permitted. It means there is no active nomination and therefore no pathway. A 503A pharmacy may only compound with a bulk substance that has a USP monograph, is a component of an approved drug, or sits on the 503A bulks list. Ipamorelin satisfies none of the three. It also was not among the seven peptides reviewed at the July 2026 advisory committee meeting.

Ipamorelin is not on the prescribing menu at major 503A compounders, and Empower does not list it.

CJC-1295: same picture, same answer. Also absent from all three FDA categories. Not on Empower’s list. Secondary sources make confident and contradictory claims about its status; treat all of them with suspicion.

MK-677 (ibutamoren): explicitly restricted. This one is unambiguous, and it is the strictest status of anything in this article. Ibutamoren mesylate is one of only six substances currently in Category 2, FDA’s designation for bulk drug substances that raise significant safety concerns. Not “under evaluation,” not “awaiting rulemaking.” Actively flagged as unsafe. It has never been approved anywhere, and it is sold as a research chemical and, illegally, as a supplement.

Somatropin (actual growth hormone): Bucket 1, FDA approved, tightly controlled, legally restricted to specific diagnoses. Not a wellness product, and very expensive.

The practical answer for anyone who wants to stay inside the law: sermorelin is available through a legitimate pharmacy because of its prior approval as Geref. Ipamorelin and CJC-1295 are not obtainable through any compliant channel, regardless of what a telehealth site tells you, and MK-677 is the one FDA has affirmatively flagged.

9. Peptides That Stimulate Testosterone in Men

Evidence tier: mixed. Read this section carefully, because this is where the marketing is worst.

The chain of command

Your testosterone production runs through a chain called the hypothalamic-pituitary-gonadal axis:

It works like a chain of command, each link giving orders to the next:

Kisspeptin signals to specialized nerve cells in the hypothalamus, deep in the brain. Those cells release GnRH in rhythmic pulses. GnRH tells the pituitary, the gland just beneath the brain, to release two hormones: LH and FSH. LH travels to the testes and instructs them to make testosterone. FSH supports sperm production.

You can intervene at any level of that chain. The level determines the effect and the honest evidence rating. It also determines what happens to your fertility, which is the part young men are rarely told about.

hCG: the LH mimic

How it works: human chorionic gonadotropin binds the same receptor LH does, directly stimulating the testes to produce testosterone. Because it acts at the testes rather than the brain, it maintains testicular size and sperm production even in a man on testosterone therapy.

Evidence: Tier 1. Decades of clinical use, FDA-approved products available.

Dosing as used: 500 to 1,500 IU subcutaneously two or three times weekly, either alone for secondary hypogonadism or alongside testosterone to preserve testicular function.

Side effects: estradiol elevation from aromatization (the conversion of testosterone into estrogen) is the most common issue, sometimes with breast tissue tenderness or growth, acne, and fluid retention.

Contraindications: androgen-dependent cancer, precocious puberty.

Availability: Bucket 1 and 2. FDA-approved hCG products exist. The FDA reclassified hCG as a biologic in 2020, which complicated bulk compounding considerably, and a survey of 503B outsourcing facilities afterward found only a handful still supplying it. Some pharmacies including Empower do currently list an hCG injection. Availability has been genuinely turbulent, and that turbulence is the direct reason gonadorelin became popular.

Gonadorelin: widely used, mechanistically questionable

How it works: synthetic GnRH, one step upstream of hCG. It tells the pituitary to release LH and FSH rather than telling the testes directly.

Evidence: Tier 3 for this use, and I want to explain exactly why.

The FDA-approved product, Factrel, was withdrawn from the US market, and it was approved for diagnostic pituitary testing, not for therapy.

More importantly, gonadorelin disappears from the bloodstream in roughly two to ten minutes. The body’s own system depends on GnRH pulses arriving every ninety minutes or so. An injection once or twice a day does not reproduce that rhythm.

And there is a deeper problem, which is worth understanding because it is genuinely counterintuitive. A steady, non-pulsing GnRH signal does not turn the system up. It shuts it off. The receptor stops responding when the signal never lets up.

This is not a theoretical concern. It is the exact mechanism we use deliberately, with drugs like leuprolide, to shut down testosterone production in advanced prostate cancer. The rhythm of the signal, not merely its presence, decides whether the system switches on or off.

Clinicians using gonadorelin are applying mechanistic reasoning to fill the access gap hCG left behind. The 2025 reviews in Translational Andrology and Urology and Nature Reviews Urology both note the clinical evidence base remains sparse.

Dosing as used: 100 to 200 mcg subcutaneously once or twice daily, or every other day.

Availability: Bucket 2, and available today. Empower currently lists a gonadorelin injection among the compounded products it can prepare with a prescription. So this one is legitimately obtainable, which creates the odd situation where the peptide with the weakest rationale in this section is the easiest to get.

I include it because patients ask constantly, not because I find the pharmacology persuasive.

Kisspeptin: the upstream target with real science behind it

How it works: kisspeptin acts on the GnRH nerve cells and is the master switch for the entire reproductive system. We know it is essential rather than merely helpful for a stark reason: people born with a broken version of its receptor never go through puberty at all.

Evidence: Tier 2, and genuinely strong for a research compound. Waljit Dhillo’s group at Imperial College London demonstrated dose-dependent LH, FSH, and testosterone release in healthy men. A 2023 randomized crossover trial in 32 men with hypoactive sexual desire disorder showed measurable changes in sexual brain processing and increased penile tumescence versus placebo.

The limitation nobody selling it mentions: Jayasena’s work showed tachyphylaxis with twice-daily dosing. Tachyphylaxis means the receptor stops responding when you stimulate it continuously. Continuous kisspeptin defeats itself, which makes any daily kisspeptin protocol biologically incoherent.

Dosing in research: kisspeptin-10 boluses at 0.1 to 1.0 nmol/kg; kisspeptin-54 at 0.3 to 9.6 nmol/kg subcutaneously.

Availability: Bucket 3, and more restricted than most people realize. Kisspeptin is not FDA approved for any indication. More than that: kisspeptin-10 is one of only six substances currently sitting in FDA’s Category 2, the designation for bulk drug substances that raise significant safety concerns, on the list updated May 14, 2026.

That is worth pausing on. The compound with arguably the best academic research program in this entire article is also one of the most restricted. It reflects FDA’s judgment about compounding safety, not a verdict on the science. But it does mean there is no legitimate US channel, and research-chemical sourcing is the only route, which I would not use.

What is not a peptide

Enclomiphene and clomiphene are SERMs, not peptides. A selective estrogen receptor modulator blocks estrogen’s feedback signal at the pituitary. The pituitary concludes estrogen is low and responds by releasing more LH and FSH, which raises your own testosterone production rather than replacing it.

I am including them here despite the category mismatch, for two reasons. They get marketed alongside peptides constantly, and in my own practice they are frequently the more sensible tool. I use clomiphene regularly in men with hypogonadotropic hypogonadism as an alternative to testosterone replacement, and my experience with it has been very positive. For a younger man who wants to preserve fertility, stimulating your own axis and shutting it down are very different decisions.

Enclomiphene versus clomiphene: is the newer one actually better?

Patients ask this constantly, and there is a real answer.

The pharmacology is genuinely different. Clomiphene is a mixture of two mirror-image forms. Roughly 62% is enclomiphene, which is the anti-estrogen doing the useful work. About 38% is zuclomiphene, which behaves as an estrogen agonist, the opposite of what you want. Their half-lives are wildly different: enclomiphene clears in about 10 hours, while zuclomiphene persists for weeks and remains detectable more than a month after a dose. So on clomiphene you accumulate the estrogenic component while the useful component comes and goes.

Enclomiphene is simply that mixture with the estrogenic half removed.

What the head-to-head data shows. A 2024 study followed 66 men switched from clomiphene to enclomiphene:

Testosterone response was comparable. Enclomiphene produced a median rise of 166 ng/dL versus 98 ng/dL for clomiphene, and that difference was not statistically significant.
Estradiol clearly favored enclomiphene. Estradiol fell slightly on enclomiphene and rose meaningfully on clomiphene, a difference that was statistically significant.
Side effects were less frequent on enclomiphene, with significantly fewer reports of decreased libido, low energy, and mood changes.

How I read that. The advantage is real, but it is a tolerability and estradiol advantage, not an efficacy advantage. Both raise testosterone comparably. If a man does well on clomiphene without estrogenic side effects, there is no strong reason to switch him. If he is getting mood changes, breast tenderness, or a rising estradiol, the pharmacology gives you a specific reason to expect enclomiphene to do better, and the data supports it.

Anyone claiming enclomiphene raises testosterone better is overstating what the study found.

Availability: enclomiphene is not FDA approved. Its manufacturer discontinued development in 2021, and it currently sits in FDA’s Category 1, meaning under evaluation with compounding tolerated in the interim. It is widely available compounded, including from Empower. Clomiphene, by contrast, is an FDA-approved drug used off-label in men and available as a generic, though I would note that generic pricing on it has not been stable.

Monitoring I would want for any intervention on this axis

Total and free testosterone, LH, FSH at baseline and follow-up
Estradiol by sensitive LC-MS/MS assay, not the standard immunoassay, which performs poorly at male concentrations
SHBG, hematocrit, PSA in men over 40
Semen analysis before and during, if fertility matters to you at all
Comprehensive metabolic panel and lipids

The full evaluation is in my posts on low testosterone and men’s sexual health and low libido, and on my men’s hormone health page. It is also worth reading about environmental chemical exposure and testosterone, because in a meaningful number of men that is the actual driver and no peptide will fix it.

The point I make with every man who asks about this: stimulating your own production and replacing it from outside are fundamentally different decisions with different consequences for fertility. Too many young men are shut down by clinics that never had that conversation with them.

10. Peptides in Women’s Reproductive and Sexual Health

Evidence tier: 1 for the approved agents. Tier 2 for kisspeptin. Nonexistent for what most people are actually asking about.

The disappointing answer first

Women ask me whether BPC-157 or TB-500 will help endometriosis, fibroids, or PCOS.

There is no literature, animal or human, on those peptides in those conditions. Not positive, not negative. Nothing. Dr. Bakri was asked exactly this on the podcast and gave the same answer.

These are hormonal and metabolic conditions, and the hormonal lever is far more powerful than any repair peptide. For PCOS in particular, insulin resistance is where the leverage actually is, which I have written about here.

Anyone selling repair peptides for endometriosis is selling something with zero evidentiary basis.

The peptides that genuinely are standard of care

Reproductive endocrinology has used peptide drugs for decades. They are simply not marketed as “peptide therapy,” which is a marketing distinction rather than a scientific one.

GnRH agonists (leuprolide, nafarelin, goserelin, triptorelin). Given continuously, they exhaust and downregulate the pituitary GnRH receptor, producing a temporary low-estrogen state. Used in endometriosis, fibroids, and IVF suppression. Tier 1 and genuinely effective. Side effects are the expected low-estrogen ones: hot flashes, vaginal dryness, mood changes, and bone mineral density loss, which is why add-back hormone therapy and DEXA monitoring exist and why use beyond six months needs real justification.

GnRH antagonists (cetrorelix, ganirelix). These block the receptor immediately without the initial surge, used to prevent a premature LH surge during IVF.

Gonadotropins (follitropin alfa and beta, menotropins, and hCG or a GnRH agonist as the ovulation trigger). Ovulation induction and IVF. Tier 1, with ovarian hyperstimulation syndrome and multiple pregnancy as the main risks.

All of these are FDA approved, Bucket 1, and available through any pharmacy with a prescription from a reproductive endocrinologist.

Kisspeptin: the most interesting development in this space

As an IVF trigger. Kisspeptin-54 triggers final egg maturation through your own GnRH pathway. Its half-life is roughly 28 minutes versus about 36 hours for hCG, so the LH surge is shorter and more physiologic. That dramatically reduces the risk of ovarian hyperstimulation syndrome, a potentially dangerous complication where the ovaries swell and fluid shifts out of the bloodstream. Abbara and Dhillo’s phase 2 work at Hammersmith showed successful egg maturation with near-elimination of OHSS in high-risk women, including PCOS patients with high follicle counts. Typical protocol: 9.6 nmol/kg subcutaneously.

In functional hypothalamic amenorrhea. When periods stop because of energy deficiency, stress, or excessive exercise, kisspeptin-54 restores LH pulsatility. That proves the axis is intact and recoverable, which is genuinely useful diagnostic information.

It does not make kisspeptin the treatment. Twice-daily dosing produces tachyphylaxis, and restoring energy availability remains first line. Anyone offering peptide injections for hypothalamic amenorrhea instead of addressing the underlying energy deficit has the physiology backwards and is treating a signal rather than a cause.

Availability: Bucket 3. Not FDA approved, research channels only.

Bremelanotide (PT-141): the one FDA-approved peptide for sexual desire, and it works in both sexes

This is the entry most people do not know exists, so I want to spend real time on it.

How it works: bremelanotide is a small ring-shaped peptide that acts in the brain, on the pathways governing desire itself, and it does so regardless of estrogen or testosterone levels.

That independence is the clinically valuable part. It works in women whose hormones are already optimized and in men whose testosterone is already normal. It is not a hormone and it is not a blood flow drug. Where Viagra and Cialis act on the vascular plumbing, bremelanotide acts on the wiring for desire itself. Those are different problems, and confusing them is why a lot of people get treated for the wrong one.

Evidence in women: Tier 1. FDA approved in 2019 as Vyleesi for acquired, generalized hypoactive sexual desire disorder in premenopausal women, based on the RECONNECT program, two phase 3 randomized trials enrolling 1,267 women (Kingsberg et al., Obstetrics and Gynecology, 2019).

Evidence in men: Tier 2. Phase 2 data support use in erectile dysfunction, including in men who do not respond to PDE5 inhibitors like Viagra and Cialis. Palatin has an ongoing phase 2b trial of bremelanotide combined with a PDE5 inhibitor for exactly that non-responder population. FDA approval for a male indication has never been pursued.

Dosing: the approved regimen is 1.75 mg subcutaneously as needed, at least 45 minutes before anticipated activity, maximum one dose per 24 hours and eight per month. Off-label protocols in men often start lower, in the 0.5 to 1 mg range, specifically to reduce nausea.

Side effects:

Nausea in roughly 40 percent of women in the phase 3 trials. This is the dominant reason people stop. Starting at a lower dose helps considerably.
Flushing and headache
Injection site reactions
Transient blood pressure increase with a compensatory drop in heart rate. This occurs in most users and is the main safety concern.
Focal hyperpigmentation with repeated use, more common in people with darker skin. This is the melanocortin family showing its origins: bremelanotide is chemically derived from melanotan II, the tanning peptide.

Contraindications: uncontrolled hypertension, known cardiovascular disease, pregnancy.

Availability: this is the nuanced one, so read carefully.

Vyleesi is Bucket 1. It is a real FDA-approved pharmaceutical autoinjector, available by prescription at retail pharmacies. Prescribing it off-label for men is legal, and off-label prescribing of approved drugs is routine in sexual medicine. The obstacle is cost: insurance rarely covers it for women and effectively never for men, and cash price runs several hundred to over a thousand dollars per dose.

Compounded bremelanotide, usually sold as PT-141, is the route most men actually take. It is dispensed by 503A pharmacies and telehealth platforms in multi-dose vials at a small fraction of the Vyleesi price.

Its regulatory footing is genuinely contested, and you should know that before you use it. Because Vyleesi is an FDA-approved product containing the same active ingredient, compounded bremelanotide runs into the “essentially a copy of a commercially available drug” restriction, which limits when compounding is permitted. At least one regulatory tracker reports that a legacy Category 2 determination for bremelanotide was carried forward in the April 2026 update. The FDA has not taken public enforcement action against bremelanotide compounding as of mid-2026, and it is not on Empower’s current published list.

So the honest summary: the approved product is real, well-studied, legal to prescribe off-label to men, and expensive. The compounded version is widely available, far cheaper, chemically identical in principle, and standing on shakier legal ground than the telehealth sites advertising it suggest.

I discuss the broader workup in my posts on low libido in women and men’s sexual health, and on my women’s hormone health page.

Monitoring I would want in women

FSH, LH, estradiol, and progesterone, timed to the cycle where applicable
Total and free testosterone, SHBG, DHEA-S
AMH and antral follicle count for fertility assessment
Full thyroid panel with antibodies. Thyroid dysfunction masquerades as reproductive dysfunction constantly, and I catch it regularly in women who were told everything was normal.
Fasting insulin and HbA1c where PCOS is suspected
DEXA for any prolonged GnRH agonist course
Blood pressure before considering bremelanotide

Quick Reference: What You Can Actually Get in the US Right Now

Two different questions get confused constantly: what the advisory committee recommended, and what you can actually obtain. They are separate columns for a reason.

Peptide	Can you get it now?	July 2026 PCAC vote	Where it comes from
Tesamorelin (Egrifta)	✅ FDA APPROVED	not reviewed	Retail pharmacy; approved only for HIV lipodystrophy
Bremelanotide (Vyleesi)	✅ FDA APPROVED	not reviewed	Retail pharmacy; approved for premenopausal HSDD, legal off-label for men
hCG	✅ FDA APPROVED	not reviewed	Retail pharmacy; compounding supply has been turbulent
Sermorelin	✅ COMPOUNDABLE TODAY	not reviewed	503A pharmacy with prescription (Empower and others)
Gonadorelin	✅ COMPOUNDABLE TODAY	not reviewed	503A pharmacy with prescription (Empower and others)
GHK-Cu, non-injectable only	✅ COMPOUNDABLE TODAY	not reviewed	FDA Category 1 as “GHK-Cu (except for injectable routes)”
Enclomiphene (a SERM, not a peptide)	✅ COMPOUNDABLE TODAY	not reviewed	503A pharmacy with prescription
BPC-157	❌ Not legitimately available	Recommended 8–6	Rulemaking pending, into 2027
TB-500	❌ Not legitimately available	Recommended 8–6	Rulemaking pending, into 2027
KPV	❌ Not legitimately available	Recommended 8–6	Rulemaking pending, into 2027
MOTS-c	❌ Not legitimately available	Recommended 7–5	Rulemaking pending, into 2027
Epithalon	❌ Not legitimately available	Recommended 7–5	Rulemaking pending, into 2027
Semax	❌ Not legitimately available	Recommended 8–5	Rulemaking pending, into 2027
Emideltide (DSIP)	❌ Not legitimately available	Rejected 6–7	The meeting’s only rejection
Thymosin alpha-1	❌ Not legitimately available	not reviewed	Approved in 35+ countries, not the US
Ipamorelin	❌ Not legitimately available	not reviewed	On none of FDA’s three categories; no pathway
CJC-1295	❌ Not legitimately available	not reviewed	On none of FDA’s three categories; no pathway
GHK-Cu injectable	❌ Not legitimately available	not reviewed	Explicitly excluded; PCAC review by Feb 2027
Kisspeptin-10	❌ Not legitimately available	not reviewed	FDA Category 2 (significant safety concerns)
Pinealon (EDR)	❌ Not legitimately available	not reviewed	OTC in Russia; research chemical here
Thymulin	❌ Not available anywhere	not reviewed	FDA Category 3; no product exists
MK-677 (ibutamoren)	❌ Not legitimately available	not reviewed	FDA Category 2 (significant safety concerns)

Read that middle column carefully. A recommendation is a committee saying the FDA should consider allowing compounding. It is not approval, it is not permission, and it changed nothing at any pharmacy on July 25. Six peptides got a favorable vote. Zero of them became available.

I checked the largest and most rigorously accredited compounder in the country on July 28, four days after the vote. Their list of peptides available to prescribe was unchanged. It still is.

Category statuses above come directly from FDA’s own 503A bulk drug substances category list, which I read on August 5, 2026, at which point it carried an update date of May 14, 2026. Not from secondary reporting or industry summaries. The GHK-Cu entry is quoted verbatim, parenthetical included. Vote margins are from the July 23 to 24, 2026 Pharmacy Compounding Advisory Committee meeting, docket FDA-2025-N-6895.

One caution about that link: FDA revises this document in place rather than archiving versions. If you open it months from now, the entries may no longer match what I have quoted here. That would mean my snapshot has aged, not that either of us is wrong.

One detail from that FDA list is worth stating plainly, because it undercuts a lot of marketing. Most of the peptides in this article appear on none of FDA’s three 503A categories at all. BPC-157, TB-500, KPV, MOTS-c, epitalon, Semax, thymosin alpha-1, ipamorelin, CJC-1295, and sermorelin are absent from Category 1, Category 2, and Category 3 alike.

Let me be precise about what that does and does not mean, because this is where writing on the subject usually gets sloppy.

There are two separate bulks lists, and neither one has these peptides on it. The 503A list governs patient-specific compounding at traditional pharmacies. The 503B list governs outsourcing facilities that make larger batches. The 503B list is remarkably short. As of its last update it contains five substances: diphenylcyclopropenone, glycolic acid, quinacrine HCl for oral use, squaric acid dibutyl ester, and trichloroacetic acid. Not one peptide.

Absent from all of these lists is not a loophole. Under Section 503A, compounding with a bulk substance requires a USP monograph, status as a component of an FDA-approved drug, or placement on the 503A bulks list. Being unlisted means the third door is shut, and for these compounds the first two were never open either.

Sermorelin and gonadorelin are the exceptions on this page, and the reason matters. Both were once FDA-approved finished products, Geref and Factrel respectively. That makes their active ingredients components of approved drugs, which is an entirely separate statutory pathway that has nothing to do with the bulks list. It is why a pharmacy can hand you sermorelin today and cannot hand you ipamorelin, despite neither one having a current FDA approval.

And a favorable committee vote does not create a pathway. It recommends that FDA consider opening one.

Two further caveats I want to be honest about. A recommendation for the 503A list should not be read as saying anything about 503B facilities, office stock, particular dosage forms, or what any individual state board of pharmacy permits. State law adds another layer on top of all of this. And regulatory status here has changed several times in three years, so anything in this article, including the sentence you are reading, deserves independent verification before you act on it.

Sourcing: The Risk That Never Makes It Onto the Sales Page

Everything above assumes you are actually getting the compound on the label. For a large share of this market, that assumption is not supported.

Every peptide raw material originates in China. There is no such thing as an American-made peptide active ingredient at present. Domestic facilities finish and package it. That is true for the pharmaceutical supply chain and the gray market alike, and it is not by itself a red flag.

The differences appear downstream.

FDA-approved pharmaceutical products carry full purity, potency, and sterility guarantees.

Licensed 503A and 503B compounding pharmacies vary, and the good ones make it easy to tell. Look for PCAB accreditation, USP 795, 797, and 800 compliance, ingredients sourced from FDA-registered facilities, third-party testing, and published stability data supporting the beyond-use date. Empower publishes all of that. So do several others including Hallandale, Olympia, and Belmar. Ask for the certificate of analysis. If the pharmacy hesitates, you have your answer.

“Research use only” gray-market vendors, where the majority of peptides are actually purchased, offer no assurance of identity, purity, sterility, or batch-to-batch consistency. The label saying “not for human consumption” is not decorative. It is the legal structure that lets the product exist without any of the testing you would otherwise be entitled to.

The failure mode is not hypothetical. One widely circulated case involved a man who ordered retatrutide, noticed he was tanning inexplicably, and worked out that he had been injecting melanotan II.

Black market is a further step down: vials bought directly from an overseas supplier through a messaging app, or synthesized by someone with no facility at all. Do not.

A word about physician incentives, including mine

Dr. Bakri raised this on the podcast and I am going to repeat it, because it applies to my own field and to me.

Clinics routinely buy compounded products from a pharmacy at cost and resell them to patients at a substantial markup without disclosing the margin. That arrangement creates a direct financial incentive to prescribe regardless of whether the evidence supports it for you specifically.

You are entitled to ask any physician what they pay for a compounded medication and what they are charging you. Ask me. Ask anyone. A physician who will not answer that question has told you something important.

As I said at the top, I have not prescribed peptides so far, and I take no margin on any compounded product. That is not a virtue, it is simply a fact worth knowing when you are deciding whose assessment to trust. It may change as the evidence changes. What will not change is that I will tell you what I am charging and why.

How I Would Approach This With a Patient

I do not offer peptide injections. What I do is evaluate whether any of this makes sense for a specific person, which usually means starting somewhere other than the peptide.

Nothing before the basics. Sleep, morning light exposure, whole-food nutrition, resistance training, and stress load come first. A peptide layered on top of five hours of sleep and a processed-food diet is an expensive placebo. This is not a throwaway line: I have seen fatigue, low libido, and poor recovery resolve completely on those five things alone.

Rule out the endocrinology first. A remarkable number of people who arrive asking about peptides turn out to have undiagnosed hypothyroidism, untreated sleep apnea, iron deficiency, vitamin D deficiency, or genuine hypogonadism. Those have real treatments with real evidence, and treating them properly is usually more transformative than anything on this list.

Be explicit about the evidence tier. I would tell you plainly when a compound has decades of human data and when we are extrapolating from rodents. Those deserve different levels of confidence and different levels of risk tolerance.

Define the endpoint and the stop date before starting anything. What exactly are we measuring, and at what point do we conclude it did not work? Open-ended peptide protocols are a business model, not a treatment plan.

Screen for the contraindication that matters. Age-appropriate cancer screening current before anyone considers a compound that promotes blood vessel growth or activates telomerase. I would not be flexible on this.

Monitor the labs. IGF-1, glucose and HbA1c, full thyroid panel, sex hormones with a sensitive estradiol assay, CBC with differential, PSA where indicated.

Source it through a legitimate pharmacy or do not do it. If the only way to obtain something is a website that says “not for human consumption,” that is the answer.

The Honest Summary

Peptide medicine is in a strange position right now.

There is real signal here. Thymosin alpha-1 has legitimate approval in more than thirty-five countries. Tesamorelin has FDA approval. Bremelanotide has FDA approval and two positive phase 3 trials. Kisspeptin has genuinely promising reproductive endocrinology data from a serious academic group. Topical GHK-Cu has reasonable cosmetic evidence and is legally available today.

There is also an enormous amount of confident marketing built on rodent studies from single research groups, sold through channels with no quality control, at prices that make somebody a great deal of money.

As Dr. Bakri framed it, and I think this is exactly right: either these compounds are as useful as their proponents claim, in which case millions of people were denied something valuable for years, or they are ineffective or harmful, in which case millions of people are injecting them right now. Both outcomes are bad. Both are the consequence of the same failure to generate real data.

The 2026 regulatory changes will expand access. They will not generate evidence. Those are different things, and the gap between them is exactly where patients get hurt.

If you want to think through peptides with someone who will tell you which tier the evidence actually sits in, including when the answer is that you should not bother, that is the conversation I am set up to have.

Schedule a Consultation in Fairfield, CT

I am a board-certified endocrinologist with twenty-five years of clinical experience, fellowship-trained at Montefiore and Albert Einstein College of Medicine and trained at Mount Sinai, with full functional medicine certification through the Institute for Functional Medicine. You can read more about my background and approach here.

Peptide questions deserve an endocrinologist, not an order form.

Restore Health LLC

501 Kings Highway East, Suite 103, Fairfield, CT 06825

(203) 760-5544

Book your consultation, see what to expect as a patient, browse the full blog archive, listen to the audio health guides, or see the areas I serve throughout Fairfield County and beyond.

This post is for informational and educational purposes only and does not constitute medical advice. None of the peptides discussed are FDA approved for general wellness use, and dosing information is reported to describe current practice, not to recommend it.

Everything here, particularly anything about legality, availability, and where a compound can be obtained, reflects August 5, 2026. This area is changing rapidly, with FDA decisions pending on the six recommended peptides and separately on injectable GHK-Cu. If you are reading this later, verify before acting. Peptide therapy should only be undertaken under the supervision of a qualified physician.

Restore Health LLC

Peptide Therapy in 2026: An Endocrinologist’s Evidence Review of 10 Peptide Classes

Contents

Peptide Therapy in 2026: What Changed, and What the Evidence Actually Shows

Start Here: What Is a Peptide, and Why Does the Category Barely Make Sense?

Three Categories: Approved, Compoundable, and Neither

What the July 2026 Vote Actually Did

And here is the part the marketing leaves out

How I Grade the Evidence Here

📞 Thinking about peptides? Get the endocrinology sorted first.

1. BPC-157: The Most Discussed, Least Proven Peptide in Medicine

Where it came from

How it works

What it is used for

Efficacy: what we actually know

Dosing as actually used

Side effects

The cancer question, which is genuinely contested

Other cautions

Duration

Monitoring I would want

Availability in the US right now

2. TB-500 and Thymosin Beta-4: The Other Half of the “Wolverine Stack”

How it works

Indications and efficacy

Dosing as used

Side effects, contraindications, duration, monitoring

Availability in the US right now

3. Thymosin Alpha-1: The Best-Evidenced Peptide Almost Nobody Talks About

Background biology: the thymus

How thymosin alpha-1 works

Indications and efficacy

Dosing

Side effects and contraindications

Duration and monitoring I would want

Availability in the US right now

4. Thymulin: The Peptide You Cannot Buy, and the Intervention You Can

Why this one is clinically useful even though you cannot get it

The honest translation

Availability in the US right now

5. Pinealon (EDR): A Tripeptide That Is Not From the Pineal Gland

What it actually is

How it works

What it is used for

Dosing

Side effects and contraindications

Duration and monitoring I would want

Availability in the US right now

6. Epithalon (Epitalon): Telomerase, Melatonin, and a 15-Year Study Worth Scrutinizing

How it works

The longevity data

Dosing

Side effects and contraindications

Duration and monitoring I would want

Availability in the US right now

7. GHK-Cu: The Copper Peptide, and the One Peptide on This List You Can Actually Get Today

How it works

Indications and efficacy

Dosing

Side effects, contraindications, monitoring

Availability in the US right now

8. Growth Hormone Secretagogues: Where Endocrinology Actually Has Something to Say

The two mechanisms people constantly conflate

The question underneath all of this

Regulatory status and what each one is

Dosing as used

Side effects: the part most clinics skip past

Contraindications

Duration

Monitoring I would want, and would not compromise on

Availability in the US right now, including the ipamorelin question

9. Peptides That Stimulate Testosterone in Men

The chain of command

hCG: the LH mimic

Gonadorelin: widely used, mechanistically questionable

Kisspeptin: the upstream target with real science behind it

What is not a peptide

Enclomiphene versus clomiphene: is the newer one actually better?

Monitoring I would want for any intervention on this axis

10. Peptides in Women’s Reproductive and Sexual Health