Science

How Peptide Testing Works

What the instruments measure, what a certificate can and cannot establish, and what published research has found. Written to be understood without a chemistry background.

The methods

What the laboratory actually does to your sample, and why the method on the certificate matters.

Start with this one How a peptide gets made, one link at a time At 99% efficiency per step, a 39-link chain comes out right only two thirds of the time. That single piece of arithmetic explains almost every quality problem in this market. ~6 min · no chemistry assumed Explained simply How does a lab know what’s in your vial? Older methods time how long a molecule takes to travel through a tube. Mass spectrometry weighs it, then breaks it and weighs the pieces. Two runners can tie; two molecules rarely weigh the same and shatter identically. ~5 min · no chemistry assumed Explained simply A vial can be sterile and still contaminated Endotoxin survives autoclaving and passes straight through sterile filters. Purity does not predict it — the correlation is effectively zero. Here is what it is and how it gets measured. ~5 min · no chemistry assumed In progress How to read a certificate of analysis Line by line through a real report — what each number means, which ones matter, and which are quietly missing from most certificates you will be shown. Coming soon

What testing finds

Published research, cited and linked, with the sample sizes stated plainly.

The one most people get wrong Purity is not content Your vial can be 99% pure and still hold a quarter less peptide than the label says. Both figures are honest — they answer different questions, and most certificates only answer the easy one.
Peer-reviewed What researchers found in unregulated semaglutide Vials labelled 99% pure measured between 7.7% and 14.4%, with endotoxin in every sample — while total content exceeded the label. Three vials, one study, all caveats stated. J Med Internet Res, 2024 · n=3 In progress What we find Once we have run enough samples to say something meaningful, the aggregate results go here — anonymised, batch-level, and published whether or not they flatter anyone. Coming soon

The market itself

Who makes this, who fills it, who ships it — and which of them is obliged to check anything.

The supply chain Who actually makes the peptide in your vial? Four or five businesses handle it before you do, and each knows only its neighbours. Every layer adds a name; none of them adds accountability. No vendors named. ~7 min · structural, not sourcing In progress What changed when Canada approved generic semaglutide The first G7 approval of a generic GLP-1 changes the calculus for one compound and nothing at all for the others. Which is which, and why. Coming soon
In progress What our certificate does and does not prove A certificate establishes some things and not others. Which measurements it settles, which questions it leaves open, and how to tell one from the other. Coming soon In progress Why not just send it to the lab yourself? We name the laboratory on every certificate, so you could. Here is an honest account of what you would gain, what you would give up, and when going direct is the better call. Coming soon In progress CJC-1295 with DAC, or without? Two different molecules, one name, 280 daltons apart. The most common labelling confusion in the category, and why reading the label cannot resolve it. Coming soon

Why we publish this at all. Every page here makes it easier to test a peptide without using us. That is the point. A customer who understands what a certificate means is a customer who can tell a good one from a bad one — including ours.

We would rather compete against informed buyers than sell to people who cannot check our work.