Peptides: Hype vs. Evidence

Read This First

The podcast said it fixed his shoulder in three weeks. The clinic page calls it a "healing peptide". The website you were sent to has a photo of a clean white vial, a purity percentage, and a line in small grey type at the bottom: for research use only, not for human consumption.

You noticed that line. Everyone does. And you probably decided it was a legal formality, a wink between the seller and the buyer.

This book is about the gap between those three things: what the podcast promised, what the clinic implied, and what that small grey line actually means.

Sound familiar?

• You first heard the name BPC-157, TB-500 or "reta" from a podcast, a gym friend or a video, not a doctor.
• You've read "research use only" on a site that also sells the syringes.
• You've looked at a certificate of analysis and felt reassured, without knowing who wrote it.
• You've thought, "It's just amino acids. How bad can it be?"
• You've already ordered, or you have a basket open in another tab.

If you're nodding, this book was written for you. Not to stop you. To make sure you go in knowing what you're actually buying.

What this book is

It is the honest evidence on the peptides people are actually buying: the "healing" ones (BPC-157, TB-500), the growth-hormone ones (CJC-1295, ipamorelin, MK-677), the tanning and libido ones (Melanotan, PT-141), the grey-market weight-loss drugs (research semaglutide, tirzepatide, retatrutide), and the longevity and brain peptides (Epitalon, MOTS-c, Semax, Selank and friends).

For each one you will learn four things:

1. Is it an approved medicine anywhere, and for what?
2. What is the human evidence? Strong, weak, or none at all. Most of the time the honest answer is "rats, cells, and a handful of people".
3. What can go wrong? The known risks, the theoretical ones, and the ones nobody has looked for yet.
4. What is likely to be in the vial you'd actually buy, which is often a different question from what the label says.

It also covers how to judge a peptide clinic, what to watch for after an injection, and when to go straight to an emergency department.

What this book will never give you

No doses. No cycles, "protocols" or stacks. No reconstitution or injection instructions. No seller names, no "trusted supplier" lists, no discount codes, nothing about getting products past customs or testing.

That isn't squeamishness. It's because the honest answer to "what's the right dose of BPC-157?" is that nobody knows. There is no tested human dose for most of these compounds, and a number printed in a book would look like a fact when it is a guess copied from a forum. The shelf already has plenty of books selling that guess. This one tells you what is known and what isn't.

Not medical advice

This book is education and harm reduction. It is not medical advice and it is not a substitute for an assessment by a licensed clinician who knows your health history. MediQuestAI does not prescribe, sell or dispense anything, and nothing in this book is a recommendation to buy or use any product.

Stories. Some stories in this book are composites; names and details are changed. Where a story is a documented public case (a court ruling, a regulator action, a published case report, reputable reporting), we say so and cite the source.

Evidence. Every number in this book carries a citation. Where the evidence is only animal studies, case reports or one small trial, the text says so. Approval status, compounding rules and anti-doping lists change; every such claim is dated "as of" October 2026. Check the current position before you rely on it.

Danger now?

If you or someone with you has injected something and has swelling of the lips, tongue or throat, wheezing or trouble breathing, or feels faint, call emergency services now (999 in the UK and Kenya, 911 in the US, 112 in the EU).

Also go now for spreading redness, heat or pus from an injection site with fever or chills, an erection that won't go down after 3 to 4 hours, chest pain, or shaking and confusion after a weight-loss injection.

The full list is on the Go Now Card at the back of this book. Read it once now, before you need it.

How to read this book

• Chapters 1 to 4 build the frame: why peptides are everywhere, what a peptide actually is, which ones are licensed medicines, and the legal grey zone where everything else lives.
• Chapters 5 to 9 are the peptide families. Jump straight to the one you're considering. Each one stands alone.
• Chapters 10 to 12 apply to everyone: what is really in an unregulated vial, the infection and allergy risks of injecting, and how to decide, with or without a clinician.

At the back you'll find the Go Now Card, the Peptide Reality Check worksheet, a glossary and the full references.

Do this now

Write down the name of every peptide you are considering or already using, and where you first heard about each one. You'll fill in the rest of the Peptide Reality Check as you read.

The one thing to carry from this page: a "research use only" label means nobody has checked that what's in the vial is safe to put in a human, including the person who sold it to you.

About this book

This book is educational. It is not medical advice, and it is not a substitute for a clinician who knows your history. If you have warning signs now, use the Go Now card or call your local emergency number. For everything else, take the questions in this book to a doctor, nurse or pharmacist.

The Peptide Gold Rush

In 2012, players at the Essendon Football Club, one of the biggest names in Australian Rules football, lined up for injections. The club was running a supplements programme designed by a sports scientist. The players signed consent forms. The forms said the substances complied with the World Anti-Doping Agency (WADA) code.

These were professional athletes, with club doctors, club lawyers and a whole industry watching their every move. In February 2013 the club itself asked the league and Australia's anti-doping agency to investigate. In March 2015 the league's anti-doping tribunal cleared all 34 players who had been charged.

Then WADA appealed. In January 2016 the Court of Arbitration for Sport found that the 34 past and present players had been given thymosin beta-4, a banned peptide. A synthetic fragment of it is what gyms and websites now sell as TB-500 (Chapter 5). Each was banned for two years. The club's captain had already admitted, back in 2013, that he had been given another peptide, AOD-9604. The sports scientist at the centre of the programme was banned for life.

Here is what Essendon's players did not know, and what this chapter is about: the person telling you about a peptide is almost never the person who has checked that it is safe in humans, and for most of these compounds nobody has. Thirty-four professional footballers, with doctors and signed forms, still did not know what went into their bodies. You, ordering from a website at midnight, have less protection than they did.