Peptide CornerPEPTIDE CORNER

Know if your peptides are real before you use them.

Anyone can email you a lab report that looks legitimate. Very few people know which lines on it to check — and the people selling to you know that. Four free guides give you the checks, starting from the plain-English basics: what a certificate can and can’t show, what actually degrades a peptide, and how to tell whether a study means anything.

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Four guides · one email · no cost.

Peptides, Plainly — the free beginner’s guideThe 12-Point COA Quick-Check (blurred preview)The Peptide Storage Reality CheckHow to Read a Peptide Study Like an Engineer4 guides · free
Hundreds of identical sealed glass vials in rows on a laboratory bench

Most vials are fine. The problem is the ones that aren’t.

Someone finally tested this market properly — 6,441 samples, 14 compounds, 203 different sellers. The typical vial came back 99.8% pure, which is genuinely reassuring. Then you look at the tail end.

1 in 10

Nothing in the vial

For some compounds, the peptide on the label simply wasn’t there. Not underdosed — absent.

15%

Carried endotoxin

The stuff that gives you a fever. A purity test is completely blind to it, so a clean report proves nothing here.

7.7%

Sold as “99% pure”

What GLP-1 vials from unauthorised sellers actually measured. A number on a store page is marketing, not measurement.

You can’t see any of this by looking at the vial. You catch it on the paperwork — which is exactly where most people give up. Sources: Mendias & Awan (2026), preprint; Ashraf, Mackey et al. (2024), J Med Internet Res.

Free download

Four free guides. One email.

Start with the plain-English basics, then one guide for each question: is it real, is it still intact, does it do anything. None of them stop at the interesting bit. No vendor names, no doses, no cost.

  • Peptides, Plainly, the free beginner’s guide — the chemistry, maths and evidence ideas everything else rests on, from scratch. Start here.
  • The 12-Point COA Quick-Check — twelve checks in the order I’d run them and one Pass / Ask / Stop rule, on a printable card (front and back)
  • The Peptide Storage Reality Check — five things everybody repeats about storage, and none survives the check
  • How to Read a Peptide Study Like an Engineer — the eight questions to ask before you believe a headline

Your email, all four guides, done. You'll also get a short note when a new video or guide lands — unsubscribe whenever, no hard feelings.

Three questions about any peptide.

They arrive in that order, and there’s a guide for each — free versions to start with, full books when you want the whole method.

  1. 01Is it real?
  2. 02Is it still intact?
  3. 03Does it do anything?
The Sourcing Safety Blueprint
01 · Is it real?

The Sourcing Safety Blueprint

$17 USD · 49 pages

Read a Certificate of Analysis line by line, catch an altered one, and audit the seller before you ever open the lab data.

49 pages · 12 parts · a printable audit checklist

See what’s inside →

The Stability Field Manual
02 · Is it still intact?

The Stability Field Manual

$37 USD · 175 pages

What heat, water, ice and light actually do — plus 45 compounds profiled from their own published sequences.

45 compounds · 134 numbered sources · an offline calculator

See what’s inside →

The Evidence Ledger
03 · Does it do anything?

The Evidence Ledger

$49 USD · 156 pages

45 compounds graded A to E by the strongest type of evidence, with what it found and the citations printed so you can check any grade.

45 compounds · 301 citations · an offline explorer

See what’s inside →

All three together — $79 USD instead of $103

380 pages, two offline tools, three printable cards. Or start with the four free guides and see how I think first.

See the series Or start with the free guides →
Tom, host of Peptide Corner
Who’s checking this

I’m Tom. I read lab data for a living.

Chartered Chemical Process Engineer. Auditing suppliers and picking holes in technical documents is the day job. This site is that same job, pointed at peptides — with the sources printed so you can check my work.

  • CEng · Chartered Engineer
  • No vendors, ever
  • No doses, ever
  • Not a doctor — and says so

Why you can trust what’s here →

New

Or have me read your certificate for you.

Whoever sold you your peptide sent you a Certificate of Analysis. Send it to me and get back a signed engineering read of it — what it establishes, what it does not, and the questions to ask next. From $149 USD.

The COA Read →

The science, minus the sales pitch.

The three newest. Two a week, Sundays and Wednesdays — what the peptide does, what the evidence actually supports, and where it falls over.

Subscribe All videos →
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New · Does it work?

I Found The Best Way to Know If Your Peptide Actually Works

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Start here

The Peptide Mistakes Nobody Warns You About After 50

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Is it real?

What No One Tells You About Buying Peptides

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