Tracking a supplier's COA batch gaps over 14 weeks

Sep 15 933 views 12 posts

I've been logging one supplier's public COA page for 14 weeks, not reviewing an order. Batch codes go B-221 to B-238 but six are missing. Purity on posted HPLC COAs ranged 97.4–99.3%, with the two lowest values sitting right before a 9-day silence. Their domain also flipped from .is to .to in week 9, and support emails went from ~2h replies to 5 days. Could this be normal lab batching, or a red flag other source-checkers have seen?

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Six missing batch codes is a lot for one quarter.

Not necessarily. Some suppliers skip internal codes when a batch fails in-house before COA.

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The .is to .to switch is the bigger tell for me. Domains don't move for fun.

I saw that domain move too, but their WHOIS privacy just changed. Host stayed same.

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The low COAs right before the silence could mean they were re-testing, but 97.4% isn't automatically alarming depending on the assay and method. What I'd want is the chromatograms, not just the purity number. Without those, the batch gaps and domain switch are interesting but still circumstantial. Have you checked archive.org captures for the COA page dates? That would separate a real testing pause from a web redesign. If the same two batches show up later with new dates and different purity, that's one story; if they never reappear, another. I'm not saying scam, just that the signal is weak until the raw files or archives line up.

Archive.org won't catch login-walled COA PDFs. Most are gated now.

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True, but their COA index was public until week 9. I have snapshots of B-224 and B-231.

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If you have B-224 and B-231 snapshots, post the dates. The gap around B-226–B-230 is what I'm curious about. Did purity shift before or after the domain change? That's the part that would make me keep watching.

I logged 17 codes from one supplier over about three months and four of them never surfaced on the page either — when I finally asked, the answer was that those lots got quarantined in-house and never released, which weirdly made me trust the posted ones more, not less, because it meant someone was actually failing stuff instead of publishing everything. The thing that flipped it for me was that purity numbers turned out to be the least useful column in the whole log; what predicted trouble was the paperwork, since right before things went sideways their COAs switched from a lab letterhead with an address and analyst initials to a plain result table with no identifier on it, and about two weeks after that shipping stretched from 6 days to 19. So I'd ask whether your six gaps are clustered in one stretch or scattered, and whether the COA format or the lab name changed at all around week 9 — that's the thread I'd pull on before the batch numbers.

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Honestly, i’m not in the peptide sourcig weeds, but I do keep a little notebook for my walks and recipes, and the pattern thing is what gets me. Did the two low-purity COAs also have a different lab name or assay date than the others? That’s the kind of detail I’d log alongside page-capture

I’d check the PDF metadata before trusting the purity trend. Creation timestamps, producer fields, and file names often show whether a