We sent identical split samples from four commercial peptide batches to three accredited third-party labs. The purity figures that came back weren't identical — and the reasons why say more about the state of the industry than any single number could.
Every certificate of analysis makes the same implicit promise: this number is the truth about what's in the vial. So we decided to test that promise directly. Over six weeks, we split four commercial peptide batches — sourced through ordinary retail channels, the way any buyer would get them — and sent identical portions of each to three accredited third-party labs, without telling any of them the others were involved.
“A purity percentage without a method behind it is a rumor, not a result.”
— Dr. Priya Anand, analytical chemist, on what buyers should actually be asking labsA close read of the preclinical literature behind one of the most talked-about peptides in the community — and an honest accounting of the gap between animal models and everything else.
The five fields worth checking before the purity number — and what each one is actually telling you.
Most degradation happens between the lab and your doorstep — not in it. A look at where shipping actually breaks down.
How retatrutide’s three-receptor mechanism differs from the first wave of GLP-1 compounds, in plain terms.
One buyer’s timeline of a supplier relationship that ended without warning — and the questions it left behind.
The arithmetic behind mixing ratios, worked through slowly enough that it finally sticks.
Every issue, we run a few dispatches from readers — their own research, their own tracking, their own questions. These are personal accounts, not claims, and not medical advice. Read more letters →
I started keeping a proper log after reading your COA explainer — lot numbers, dates, which lab tested what. It sounds obsessive until the one week something doesn’t add up, and suddenly you’re glad you have it. Made me a much more careful buyer.
The cold chain piece finally explained something that had been bugging me for months — why two orders from the same supplier looked completely different on arrival. It was never the compound. It was August in a cardboard box.
I’ve been in this community three years and this is the first outlet that talks to us like we can handle nuance. Not everything needs to be "miracle" or "scam." Sometimes it’s just: here’s what the data says, here’s what it doesn’t.