Hi {{first name | there}},

Just a few days ago I shared dinner with a room of successful business owners, entrepreneurs, investors, and operators. These are not people who are easily impressed by vague health claims.

And still, several times someone asked me: what do you think about peptides?

I get this question all the time.

I get it. Peptides are where longevity medicine gets seriously confusing. Even in my work with CareCore, where we help other businesses set up longevity care, peptides come up constantly.

Peptide can mean insulin. It can mean GLP-1s like semaglutide or tirzepatide. It can mean a skincare ingredient.

It can also mean a freeze-dried vial shipped from China for “research use only,” reconstituted at home, and injected for tendon repair, fat loss, sleep, focus, gut healing, or “anti-aging.”

That is how one word ends up carrying both real medical progress and a lot of internet chaos.

I'm not a doctor who rolls her eyes at anything outside standard care. Some of these molecules are genuinely interesting. But I do believe in informed consent, which is making sure every person has the knowledge they need to make the right decision for their health.

I also think it's smart to avoid hurting yourself in the quest for healthspan and longevity.

Longevity is not about being first to every new trend.

It is about staying alive long enough for the useful interventions to arrive.

The FDA’s Pharmacy Compounding Advisory Committee is scheduled to meet on July 23 and 24, 2026 to discuss several peptide-related bulk drug substances for the 503A compounding pathway.

The seven substances on the agenda are:

The committee is discussing whether certain bulk substances should be considered for inclusion on the 503A Bulks List, which affects whether traditional compounding pharmacies may be able to compound them under certain conditions.

Why is this important? Access through a regulated compounding pharmacy is different - and typically safer - from buying a “research use only” vial online.

If you are going to use peptides, especially via injection, I'd urge you to source from pharmacies exercising CGMP (Current Good Manufacturing Practices). This one move can reduce your risk of an unintended error or contamination by a significant amount. The FDA's own safety-risk page for compounded bulk substances flags peptide-specific problems like immunogenicity, peptide-related impurities, active-ingredient characterization, and limited human safety information.

Peptide marketing works because peptides are real medicine.

Insulin is a peptide hormone. GLP-1 drugs changed diabetes and obesity medicine. Tirzepatide, semaglutide, and related incretin-based drugs (GLP-1 agonists and related) have changed how clinicians think about weight, cardiometabolic risk, kidney disease, liver disease, sleep apnea, and even addiction and neurodegeneration.

The pipeline is also moving quickly. A 2026 Nature Medicine review described the expanding landscape of GLP-1 medicines beyond glucose and weight. Retatrutide, a triple agonist targeting GIP, GLP-1, and glucagon receptors, produced large weight-loss signals in a Phase 2 New England Journal of Medicine trial. Novo Nordisk has filed for FDA approval of CagriSema, a once-weekly combination of semaglutide and cagrilintide, an amylin analogue.

So no, pharma is not allergic to peptides. Pharma is investing heavily in peptides when the molecule, trial design, manufacturing, patent position, and market make sense.

Meanwhile some older, cheaper, harder-to-patent molecules may not get the same development pathway as a blockbuster obesity drug. That is the real problem with the peptide boom that is not simple to solve or navigate.

The fact that semaglutide is a peptide does not validate a research vial of BPC-157. It only proves that peptide biology can be powerful when the molecule, indication, dose, manufacturing, and safety data are actually known.

When someone says “BPC-157 has evidence,” the next question should be: evidence for what?

Evidence for ulcerative colitis is not evidence for a hamstring strain. Evidence for animal tendon healing is not evidence for return to sport in humans. Evidence for a biomarker is not evidence for less pain, better sleep, fewer injuries, or longer life.

The July FDA meeting will specifically discuss BPC-157 for ulcerative colitis, KPV for wound healing and inflammatory conditions, TB-500 for wound healing, MOTS-c for obesity and osteoporosis, DSIP for opioid withdrawal, chronic insomnia, and narcolepsy, Semax for cerebral ischemia, migraine, and trigeminal neuralgia, and Epitalon for insomnia.

What I noticed immediately: These topics don't cover all the claims people see online.

Online, BPC-157 is marketed for tendon repair, gut healing, joint pain, post-surgical recovery, and the “Wolverine” stack. MOTS-c is being sold as a weight-loss or exercise-mimetic peptide. Semax is known as a focus and productivity nootropic. Epitalon is apparently a telomere and longevity peptide.

This is how evidence gets laundered if you're not discerning. A molecule has some preclinical signal, an old regional study, a mechanistic paper, or a related-compound dataset. Then the internet sells you a cleaner, broader, more confident story.

My take: look at the evidence yourself to make your own conclusions.

This is how I would make sense of the peptide noise; I'd start with the main categories.

One important caveat: the same peptide can sit in different buckets depending on the claim and the source. BPC-157 discussed as a possible compounded substance is one thing. A BPC-157/TB-500 “Wolverine stack” from a research-chemical site is a very different thing.

1. FDA-approved peptide drugs Examples: insulin; GLP-1 medicines like semaglutide; dual incretin drugs like tirzepatide. These have regulated manufacturing, labeled indications, clinical-trial evidence, known adverse-effect profiles, and a real risk-benefit frame. They can be used on-label, or sometimes off-label when the medical reasoning is clear.

2. Late-stage investigational peptide or peptide-like drugs Examples: retatrutide, CagriSema, and other incretin/amylin pipeline drugs. These may be exciting and may look available online, but they belong in trials and regulatory review, not DIY sourcing.

3. Compounding-policy candidates Examples from the July FDA agenda: BPC-157, KPV, TB-500, MOTS-c, emideltide/DSIP, Semax, and Epitalon. The question here is not “do these work for the stated claim?” It is whether certain forms can be used as bulk substances under 503A compounding rules. That could mean safer access through compounding pharmacies rather than through research-chemical sites, but it still does not create evidence where evidence is weak.

4. Wellness-clinic peptides with limited human evidence This is the bucket most readers are probably hearing about: BPC-157 for injury recovery and gut healing, TB-500 for repair, MOTS-c for metabolism or weight, KPV for inflammation, DSIP for sleep, Semax for focus, and Epitalon for longevity or telomeres. Some have plausible biology. Some have small or old human signals. Many are being marketed beyond what the evidence can actually support. A 2026 sports-medicine review made the same basic point: many unapproved peptides look interesting in animal or mechanism studies, but rigorous human safety and efficacy data are scarce.

5. Gray-market “research use only” vials Often the same names again: BPC-157, TB-500, MOTS-c, Semax, Epitalon, or blends/stacks sold online. This is the highest uncertainty zone. The question is not only whether the molecule works. It is whether the vial contains what it says, at the dose it claims, without contaminants, handled correctly, for a route that has actually been studied.

I would not treat the seven July PCAC peptides as one category. They are different molecules with different claims and different evidence problems.

BPC-157: probably the most famous injury-recovery peptide. The biology is interesting, especially in tissue repair, angiogenesis, and inflammatory models. But the human musculoskeletal evidence is still thin. A 2025 systematic review found 36 included studies, of which 35 were preclinical and only one was clinical. A newer BPC-157 musculoskeletal narrative review reached the same practical conclusion: promising preclinical biology, sparse human data, and a need for real trials. A real Phase 2 randomized hamstring-strain trial is now recruiting on ClinicalTrials.gov, which is exactly the kind of study we need.

TB-500: often marketed with BPC-157 for wound and injury recovery. The evidence problem is that public claims often borrow from thymosin beta-4 biology or related topical and ophthalmic studies, including a Phase 2 dry-eye trial of thymosin beta-4 ophthalmic solution. That is not the same as proving that injected TB-500 helps tendons, muscle tears, post-op recovery, or general athletic healing.

KPV: a tiny tripeptide with plausible anti-inflammatory biology, especially in gut and skin models. There are mechanistic reasons to care, including older Gastroenterology work showing KPV reduced intestinal inflammation in cell and mouse colitis models and a separate murine inflammatory-bowel-disease paper. But plausible anti-inflammatory biology is not the same as a patient-ready therapy.

MOTS-c: one of the more interesting metabolic peptides. It is a mitochondrial-derived peptide with preclinical links to metabolic homeostasis, insulin sensitivity, and obesity biology, including the original Cell Metabolism mouse paper. There is now a Phase 2a MOTS-c trial recruiting adults with prediabetes and overweight or obesity, and a related MOTS-c analog, CB4211, has been through an early Phase 1 NAFLD study. That is the right direction. It is not yet a proven weight-loss drug, osteoporosis drug, or exercise substitute.

DSIP, also called Emideltide: the name stands for delta sleep-inducing peptide, which is a very persuasive name. The evidence is less persuasive. There are older, small human studies in sleep, pain, and withdrawal contexts, including a 1992 double-blind chronic-insomnia study that found limited objective improvements but concluded DSIP was unlikely to have major therapeutic benefit. A 2006 review called DSIP a still unresolved riddle, which is about right.

Semax: probably has the best human signal of the seven, but mostly in older and regional cerebrovascular literature, including an older controlled acute ischemic-stroke study and a 2018 post-stroke rehabilitation study. That's very different from evidence supporting Semax as a proven focus drug, ADHD treatment, productivity enhancer, or brain-fog cure.

Epitalon: commonly sold with telomere, pineal, circadian, melatonin, and longevity language. The biology is interesting enough to read about, and there is a 2025 review of Epitalon summarizing the broader literature. There is also newer human cell-line work on telomere biology, which is scientifically interesting, but still cell biology. It is not an insomnia trial, and it is definitely not proof of longer human healthspan.

I do not think most people are drawn to peptides because they are reckless.

A lot of people are injured, tired, aging, frustrated, or sick of being told everything is normal when they do not feel normal.

A 2025 netnographic study of peptide-use forums found that use was broadening beyond bodybuilding into injury recovery, everyday wellbeing, anti-aging, and people trying to manage bodily decline. That fits the cultural moment. A lot of peptide demand is really a trust-gap story.

People want agency. They want tools. They want medicine to help them before they completely fall apart.

I am sympathetic to that. Conventional care is often too slow, fragmented, and reactive.

But ownership over one's health is not the same as turning every plausible mechanism into a personal injection protocol. Real agency requires informed consent, and informed consent requires knowing what is known, what is unknown, and what could go wrong.

When clinicians talk about safety, people often hear, “What are the side effects of the ingredient?”

That is only one layer.

For gray-market or loosely supervised peptides, the safety questions start earlier:

ProPublica reported that two women became critically ill after receiving peptide injections at RAADFest in Las Vegas and required intubation, and Nevada regulators later fined several involved parties. Investigators were not able to determine exactly why the women became ill, including whether the issue was contamination or a reaction to the peptides themselves, because they were not able to test the serums (although from the reports, it's posited that it had to do with endotoxins in the vials resulting in a sepsis-like presentation).

That story shows the real-world failure modes: unclear supply chains, licensure issues, event-booth medicine, no retained product for testing, and high-risk interventions being delivered far from a controlled clinical setting.

The risk is not only the unknown peptide.

It is the system around the peptide.

If you are considering a peptide, or if someone is trying to sell you one, these are the questions I would want answered before anyone gets near a vial.

1. What is the exact peptide? Not “a healing peptide.” Not “a mitochondrial peptide.” The exact molecule matters. Plus the strength, dose, and application method.

2. What is the exact claim? Injury healing, weight loss, gut inflammation, sleep, focus, skin repair, opioid withdrawal, migraine, and longevity are different claims.

3. What is the evidence tier? FDA-approved drug? Large human randomized trial? Small human pilot? Animal data? Cell data? Mechanistic speculation? Anecdote?

4. Does the evidence match the route? Oral, topical, nasal, subcutaneous, intravenous, and intra-articular exposure are not interchangeable.

5. Does the evidence match the population? A trial in acute hamstring strain does not prove benefit for chronic knee pain. A cerebrovascular study does not prove a nootropic effect in a healthy founder trying to work longer hours.

6. What does success look like? Pain score? MRI healing? Sleep latency? HbA1c? Insulin sensitivity? Strength? Return to sport? If you cannot define the endpoint, you are not running an experiment. You are buying a story.

7. What is the source? A COA is not enough. Sterility, endotoxin, storage, shipment, chain of custody, and legal accountability matter.

8. Who is monitoring? A peptide protocol without adverse-event monitoring and stop rules is not advanced longevity. It is unsupervised pharmacology.

9. What should come first? For most people, the higher-confidence path is still the less glamorous one: diagnose the problem, clean up sleep, nutrition, training load, rehab, cardiometabolic risk, hormones when appropriate, medications with real evidence when indicated, and targeted imaging or labs when they actually change the decision.

That may be less exciting than a vial.

It is also much more likely to be the right first move.

Peptide medicine is real. Some of it is already here. More is coming.

The gray zone is where people get into trouble: scientifically interesting molecules, thin human evidence, confident marketing, messy incentives, and variable sourcing.

I want patients to have more agency, not less. But agency depends on informed consent. And informed consent means the claim, evidence, source, route, dose, monitoring, and alternatives are all part of the decision.

If you are looking at a peptide, do not ask only whether peptides are “good” or “bad.”

Ask whether this specific peptide, for this specific claim, through this specific route, from this specific source, has earned the confidence people are giving it.

Keep Learning,

Hillary Lin, MD

If the peptide pitch that catches your eye is energy, recovery, or cellular renewal, start here first. The mitochondria episode is about the basics people skip before adding another intervention: sleep, fuel, training load, metabolic health, and whether the body has enough capacity to repair.

Watch on YouTube | Subscribe to The Longevity Show

🧪 Peptide access is moving before peptide evidence. July’s PCAC agenda could make parts of the market cleaner if some substances move through compounding. It still does not answer whether BPC-157, TB-500, or MOTS-c do what clinics are selling.

🏃 BPC-157 has a real trial now. Good. Wait for it. A Phase 2 hamstring-strain study is recruiting; until it reads out, tendon-repair claims are still mostly mechanism, animal data, and anecdotes.

🧠 The Alzheimer’s blood-test era is here. FDA cleared Lumipulse pTau217/β-amyloid for symptomatic adults 55+. Useful for diagnosis, not a wellness-panel add-on for the worried well.

🧬 Semaglutide moved aging-clock signals, but clocks are not outcomes. UCSD reported slower epigenetic-aging signals in adults with HIV-associated metabolic disease; interesting, not proof that GLP-1s extend life.

💤 Zepbound for sleep apnea is a bigger deal than the headline sounds. After SURMOUNT-OSA, GLP-1/GIP therapy is officially treating an organ-level complication of obesity, not just moving a scale number.

Dry Eye Society of the Americas Conference, July 10-11, New York, NY. A clinician-focused dry eye and ocular surface meeting.

Science of Skin Summit, September 17-20, Austin, TX. Speaking on AI in dermatology and skin and hair as windows into biological age.

MVMNT Longevity Summit, September 22-23, Coronado, CA. Speaking at a physician-focused summit on evidence-based longevity medicine, performance health, and clinical innovation.

Livelong Women's Health Summit NYC, September 25-26, New York, NY. A two-day summit on women's health, longevity, and agency. My role is still being finalized, but it is on the fall calendar.

Science of Skin Longevity Summit, February 19-21, 2027, Scottsdale, AZ. Planning to join faculty for a practical skin-longevity talk on biological age, AI/photo analysis, and the upstream biology behind what patients see in the mirror.

A few reader-supported partners that fit the longevity stack:

If you want physician-guided biological age testing, start on the testing page. It includes epigenetic age testing with consultation, plus organ-specific proteomic and SystemAge assessments when they fit the clinical question.

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