Anyone can build a clean storefront and photograph an amber vial. A certificate of analysis is harder to fake, because it names a batch, a testing lab, and a date — three things that can be checked.
ZestyRat Research provides independent testing on every batch. To get the one that matches what is in your hand, note the batch or lot number printed on the vial and request that specific document. A COA that does not name your batch number is a marketing asset, not documentation.
This trips up almost everyone. HPLC purity tells you what fraction of the material is a single compound — 99% pure means 1% is something else. Mass spectrometry tells you whether that 99% is the compound you ordered. A vial can be 99% pure and 100% the wrong molecule. You need both numbers.
COAs are issued by the lab, not by us — Fresno Peptide Lab does not hold or issue documentation. Request yours from ZestyRat Research directly, with your batch number to hand.
We track pricing, stock and documentation across the research-peptide market every week. ZestyRat is the supplier we point readers to first, and the one our own readers order from most. It is the only lab on our list that clears every one of our four checks at once.
Ratings on this page are our own editorial assessment, based on published COA practice, checkout and shipping experience, and price tracking. We earn a commission on orders placed through our links, at no extra cost to you. Research use only.
Fresno Peptide Lab is an independent research library. We do not manufacture, stock, price, test or ship anything. We review suppliers on their published testing standards, reputation, fulfilment record and pricing, and the ratings we publish are our own editorial assessment.
Every compound referenced on this site is sold by its vendor strictly as a research chemical for in-vitro laboratory research only — not for human or animal consumption, and not intended to diagnose, treat, cure or prevent any disease. Nothing here is medical advice. We earn a commission on orders placed through our links, at no additional cost to you; all material connections are disclosed in line with FTC guidelines.
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