By Justin Yamashita, MSc. Benchtop, site, CRO: three levels of basic and clinical research, explained without spin.

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Monday, The Root Room. You watch a real health claim try to work on somebody.

Wednesday, Plain Talk. One health topic from the news, taken apart in plain language, with the receipts at the foot of it.

Tuesday and Friday, The Open Site File. What the job actually looks like from inside a clinical trial site. If you or anyone you know has ever thought about moving into clinical research coordinating, start there.

Sunday, The Roots, on LinkedIn. A weekly letter for the people who get asked, the ones whose family treats them as the medical desk.

Plain Talk is Root to Rx's weekly teardown of something in the news: what happened, what the evidence says, and the one question that beats the confusion.

Peptides are short chains of amino acids. Some, like insulin, are well tested medicines. The ones trending on longevity podcasts, like BPC-157 and TB-500, mostly aren't.

Lab and animal studies suggest possible effects. High quality trials in people are scarce. In July, an FDA advisory panel voted to widen access to six of these peptides anyway, against the advice of the FDA's own scientists. That vote isn't an approval.

Below: what's known, what isn't, and the questions to ask so you can decide for yourself.

A peptide is a short chain of amino acids, the same building blocks that make up proteins, just shorter. Your body makes thousands of them. They carry signals: start healing here, release this hormone, lower blood sugar.

Plenty of peptides are proven medicines. Insulin is a peptide. So are the GLP-1 drugs like semaglutide. Each of those went through years of human trials before approval.

So "it's a peptide" doesn't tell you much on its own. The question that matters is whether this specific peptide has been tested in people, whether the one you’re buying has been produced in a safe, quality place, if there’s any actual peptide in what you’re buying at all, and potentially worse, are there any contaminants in what you’re buying that you’re injecting unknowingly.

Longevity and wellness influencers promote them for faster injury healing, better workouts, better skin and slower aging. You'll hear names like BPC-157, nicknamed the "Wolverine peptide" for injury recovery; TB-500 for recovery and inflammation; GHK-Cu for skin and hair; and epitalon, marketed for longevity. Combinations get sold as stacks.

Most are injected, and most are bought online, from clinics, or from websites that label them research use only. More on that label below.

BPC-157 is the most popular, so it's the best test case. It's a lab made peptide based on a protein found in stomach juice. Lab and animal studies suggest it may help tissue heal. In people, the evidence is thin and in previous newsletter issues we’ve talked about how something that works in animals often doesn’t mean it will work in humans. A 2025 systematic review found only small studies with no comparison group, including one where 7 of 12 people with knee pain reported relief after an injection, and it found no clinical safety data at all.

That isn't only an outside critic's view. When FDA staff reviewed it for the July meeting, they reported a lack of evidence that it works for ulcerative colitis, the use it was nominated for. One FDA scientist asked a more basic question in the meeting: what is BPC-157, exactly? He said people don't agree on its makeup, and that quality standards can't be set until that's known. Staff also noted three reports of side effects after BPC-157 injections.

For comparison, a new drug has to clear a lot before one person gets one dose: animal studies in two species, safety tests on the heart, lungs and brain, and a starting dose worked out from that data and then divided by ten. None of that is red tape for its own sake. Each step was added after something went wrong without it, and our Version History page tells those stories. Then come trials in people, usually in phases, to show a drug works and is safe enough. For most trending peptides, the human part of that story hasn't been written.

None of the trending peptides above are FDA approved for these uses. Their status has shifted three times in three years.

In 2023, the FDA put more than a dozen peptides, including BPC-157, on a list that kept compounding pharmacies from making them, citing concerns like impurities and limited human data.

In April 2026, 12 of them came off that list after the people who nominated them withdrew their nominations. They weren't added to the permitted list either, which left them in a gray zone.

In July 2026, the FDA's Pharmacy Compounding Advisory Committee voted to recommend six peptides for compounding: BPC-157, KPV, TB-500, MOTS-c, epitalon and semax. The BPC-157 vote was 8 to 6. In each case, the committee went against the written recommendation of FDA staff. News reports also raised questions about committee members' ties to the peptide business. HHS says every member went through the same ethics review required of all FDA advisers.

Here's what that vote does and doesn't do. The committee only advises so as of late September, the FDA hasn't acted. If it does, licensed pharmacies could make these peptides with a prescription. That still isn't FDA approval, and it doesn't create the missing human trials. And separately, compounding pharmacies create a logistical nightmare whose consequence can be your health.

Research use only is a real legal phrase, but it comes from the rules for lab test kits and reagents. There is no research use only category for drugs. A vial with that label hasn't been through any drug review, and the FDA has said in writing that the label doesn't change what a product is when it's being sold for people to use.

Here are seven of the ten questions in our Skeptic's Toolkit, each run against the peptide evidence. They don't tell you what to think. They tell you what to check.

Q8. How many people were studied, and has this been replicated?

For BPC-157, a 2025 systematic review turned up only small human studies with no comparison group, like one with 12 people. There's little yet to replicate. Most of the evidence comes from cells and animals.

Q6. Am I seeing the full picture, or only part of the evidence?

A testimonial shows you people who felt better and posted about it. It can't show you the people who didn't, or anything that shows up years later.

Q4. Who funded this, and do they have a stake in the answer?

Ask who profits from the claim. Clinics and sellers do, and so do some of the voices promoting peptides. That doesn't make them wrong. It means their claims need outside checking.

Q9. What do independent experts with no stake in the outcome say?

The FDA's career scientists reviewed the evidence and recommended against. The advisory panel voted the other way. Both are in the public record, so you can read each side.

Q7. Do I want this to be true, or do I want to know what's true?

This one isn't an insult. Wanting to heal faster or look younger is human. It's also the exact feeling a sales pitch is built to meet. Notice it, then keep asking.

Q10. If I'm wrong about this, what would that mean?

Without human trials, nobody can tell you the right dose, what long term use does, or what's really in a vial that no drug regulator has checked.

Q1. What evidence would actually change my mind?

For peptide fans and skeptics alike: a well designed human trial, published and repeated. That's the receipt everyone should want, and you don't have to take anyone's word on whether it exists. Type a peptide's name into ClinicalTrials.gov and you'll see whether anyone is testing it in people, and how far they've gotten. Our guide walks you through the search at our Clinical Trial Registries page.

It's your call. Some people will read all of this and still decide to try a peptide. If that's you, or if you're already taking one, tell your doctor. Peptides often don't come up in a routine visit unless you raise them, and your doctor can only factor in what they know about, from your lab results to the other medicines you take. It's easier on paper than out loud, so we made a free one page Medication and Supplement Log with room for peptides that you can fill in at home and hand over at your next appointment. Ask where the product is made, and whether it comes from a licensed pharmacy with a prescription or from a research use only website. And decide in advance what would make you stop. Consider checking out this previous issue: https://www.roottorx.com/p/r2rx-issue-017-root-room-the-room-where-they-argued-about-peptides.

For the next time someone says "BPC-157 is proven, everyone's using it":

Reply to this email or leave a comment on the newsletter: have you tried a peptide, or been pitched one? What did they say it would do, and what evidence did they show you?

The friend with the Wolverine stack in the fridge. The coworker who just started peptide shots from a longevity clinic. One person, not everyone. Use your own link below, and it counts toward your Series 1 set.

Copy and send: "Clearest breakdown I've seen of what's actually known about BPC-157 and the other peptides. Free: {{rp_refer_url}}"

Monday's Root Room, Anti-Aging Peptides: What the Longevity Pitch Leaves Out, puts you in the consult room where this pitch gets made.

Try it yourself: see if you'd have caught this week's costume on your own.

The Skeptic Type quiz sorts you into your pattern in about two minutes: openlabelmedia.com/skeptic-type.

Got Skepticism? runs any claim through five questions, including the one from this issue: how many people were studied?

Stay in the Room shows you how to disagree without a fight so that you can talk to people about these difficult topics.

The quiz and both games play in your browser at openlabelmedia.com, and I would love to see your results on social.

Work in clinical research, or want to? The Open Site File comes out Tuesday and Friday. Get it by email:

Between issues, the free tools live on the site. The Field Guide has printable patient logs and the full Skeptic's Toolkit at roottorx.com/field-guide. If you or someone you love is looking for a trial, there's a walkthrough for finding one near you at roottorx.com/clinical-trial-registries. And if you've ever wondered why clinical research has the rules it does, Version History tells that story at roottorx.com/version-history. The tees and mugs that help support the work are at shop.roottorx.com.

1. FDA Pharmacy Compounding Advisory Committee, July 23 to 24, 2026, meeting and FDA staff scientific reviews of BPC-157, KPV, TB-500, MOTS-c, emideltide, epitalon and semax, as reported by RAPS.

2. RAPS, FDA advisory committee backs two controversial peptides, July 23, 2026.

3. McDermott Will & Emery, Bulk-list bound? PCAC backs majority of peptides in two-day public meeting, July 28, 2026.

4. Buchanan Ingersoll & Rooney, FDA Advisory Committee Voted Yes on Six Peptides. Now What? The Regulatory Road Ahead, August 18, 2026.

5. STAT, New FDA peptide advisers could benefit from their own rulings, June 29, 2026; HHS statement on the committee ethics review as reported by The Washington Post, July 2026.

6. FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503A, category update of April 15, 2026 (effective April 22, 2026).

7. Vasireddi N, Hahamyan H, Salata MJ, et al. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS Journal, 2025. doi:10.1177/15563316251355551.

8. 21 CFR 809.10(c)(2)(i), labeling of in vitro diagnostic products for research use only; FDA guidance, Distribution of In Vitro Diagnostic Products Labeled for Research Use Only or Investigational Use Only, November 2013.

9. 21 CFR 312.23(a), IND content and format.

For educational purposes only. Nothing in this newsletter is medical advice. Talk to your doctor before making any health decision.

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Disclosure: Root to Rx is published independently by Open Label Media LLC. Views expressed are personal views of Justin Yamashita and do not represent his employer or any affiliated organization. No employer resources or proprietary information are used. Every claim is sourced from publicly available materials.

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