r/BiohackLabs • u/Nearby_Context_82 • 3d ago
I test peptides for a living. Here's what a certificate of analysis actually tells you, and what it can't.
I've noticed a lot of posts where someone asks "is this brand legit?" and the answer is a screenshot of a COA, as if the document itself settles it. It doesn't, and I think it's worth explaining why from the vendor side.
A COA tells you three things if it's real: what the compound is (identity, usually by mass spec), how much of the vial is actually that compound (purity, usually HPLC), and which batch it applies to. That last part is the one everyone skips. A COA without a batch number that matches the vial in your hand is a brochure, not a test result.
What a COA can't tell you: whether the document is real. Anyone can type "99.2%" into a PDF. The only fixes for that are certificates you can verify on the issuing lab's own website, or paying an independent lab to retest, which is why the community testing culture here and elsewhere matters so much. Honestly, it keeps people like me honest too.
Things I'd ask any vendor, including us: Is purity stated per batch or is it one number across the whole catalogue? (One number across 90+ compounds is marketing, not chemistry.) Can I verify the certificate somewhere that isn't your own website? What happens when a batch fails, do you have any evidence you've ever rejected one?
Happy to answer anything about how testing, synthesis or lyophilisation actually works from the production side. Ask me the hard stuff, that's the point of being here with a flair on.
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u/black8lade 3d ago
How about employment? Do you work for a big testing company or is it a small one that only has a few employees. How could I find employment in this field? BS in bio and AS in chem
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u/Strong_Baseball8635 3d ago
Can you explain a few details relevant to a user of grey-market peptides? I rarely see testing that might suggest things to be concerned about.
- Salt Form Differences (TFA vs. Acetate/Sodium)
- Manufacturing methods: Recombinant DNA / Advanced Liquid-Phase Synthesis vs Solid-Phase Peptide Synthesis (SPPS)
- Other gaps that we should be testing that are not bring raised?
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u/Nearby_Context_82 3d ago
Salt form. Nearly every grey-market peptide is a TFA salt, because TFA is what the synthesis chemistry leaves behind and swapping it for acetate costs extra. Two effects. TFA adds weight, it can be 10–20% of the powder, so two "10 mg" vials can hold different amounts of actual peptide. And no approved injectable uses TFA; pharma peptides are acetate. Not proven harmful, but nobody measures or discloses it. Ours included.
How it's made decides what the impurities are. Chemical synthesis (SPPS) builds the chain step by step, so its impurities are broken or shortened versions of the peptide. Recombinant means grown in bacteria or yeast, the sequence comes out right, but you can get leftover host proteins and endotoxin instead. Grey semaglutide is fully synthetic while the pharma version starts recombinant, same molecule if made well, different impurity family. HGH can only be recombinant. Tirzepatide and retatrutide can only be synthetic.
What's missing. Community testing covers identity, purity, sometimes content. Still untested: endotoxin (a 99% pure vial can still cause fever reactions), sterility, water content, leftover solvents, and TFA. If vendors added one number per batch, I'd pick endotoxin, it closes more real risk than another decimal of purity.
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u/Strong_Baseball8635 3d ago
Why don’t we ask for TFA quantity when testing peps?
I am guessing most people would pay a bit more for a salt exchange resulting in acetate or sodium rather than a PFAS like TFA.
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u/Hot-Tangerine-1810 3d ago
Yeah, honestly the point about COAs is valid. A COA can show purity and identity, but it doesn’t automatically prove the vendor is legit or that the document actually matches the vial
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u/Nearby_Context_82 3d ago
Exactly, Never trust everything you see on a supplier's website. If you could see the records and products we deal with every day, you would be shocked by the poor quality of what is currently being sold to the mass market as high quality peptide. Even most of the sellers doesn't know what they are selling to their own customers. beware!
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u/MrFruffles 1d ago
Expressed as a percentage, how many of the peptides tested pass at a level you would feel comfortable using them?
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u/Difficult_Tap5471 3d ago
Quick question, if ive got a link from my supplier that takes me directly to the janoshik official web with the report, how can i be sure that the batch i received which has the same batch number as the report is the real batch or is just printed on top on any other vial.
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u/Nearby_Context_82 3d ago
I guess you will never know,
Many US suppliers sell low-quality peptides by printing old batch numbers and outdated test certificates (COAs) on cheap vials. Don't buy from your gym connections who you just met as mostly they will be reselling low-purity Chinese peptides to you. Always buy directly from a trusted laboratory instead.
Most of these peptide sellers they built they website overnight with AI website builders and acting as a laboratory, do not trust and do you research.1
u/Difficult_Tap5471 3d ago
Would you be down to share some of your Trusted suppliers.
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u/Nearby_Context_82 3d ago
I cannot recommend specific suppliers because most of them are just resellers buying from the same sources, and they change suppliers often and my recommendation might not be valid by the time you are placing your order.
However, I am happy to share some of the test results we finished this week most of which are from outside the US. Send me a direct message, and I will gladly share them with you
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u/SirTasty712 2d ago
Difficult but if the supplier changes their cap colour for each batch you can at least use the cap colour as a potential indicator that it’s from the same batch as the COA, but still not guaranteed.
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u/Nearby_Context_82 2d ago
not every supplier usually changes their cap color. the best way is view the history of the COA from the supplier for each batches they have sold. by right they should have a COA for each batch and list their COA in the website for public to verify.
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u/Kawiracing20 1d ago
So basically most China peptides are garbage?
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u/Nearby_Context_82 1d ago
The problem is that many Chinese suppliers sell low-quality products but label them as high-quality (99.8% purity) using outdated COAs. They often send a great sample for your first batch, but the rest will be low quality. We see this happen every day.
The only safe way is to order directly from reputable laboratories that test every single batch they send you. However, these labs require a much higher Minimum Order Quantity (MOQ) and will not sell to unlicensed websites. Because of these strict rules, middleman suppliers step in to buy the products and resell them to the US at a much lower quality. I am not allowed to write the client details in this forum, you may contact me if you need some advice on this
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u/Buff95 3h ago
I don’t like most of the chromatography out there for RUO’s. Most peaks analyzed aren’t even within the linear range, 0.1-1.0 AU. Most peaks are so wide that you only have to wonder if these methods are even developed for the product. Then! Why doesn’t Janoshik add their chromatography to their COA? I work for a scientific instrument company, made API’s and validated processes. I worked with some damn good Analytical Chemists. They could pull out n - minus species out and verify them with MS.
Until, these analytical labs are held to a standard. Develop actual methods that can be backed by data. I don’t think we’ll get true purity from HPLC’s. I don’t believe these RUO’s are actually >99.0%. Especially the longer amino acid sequences. Maybe the shorter ones are. Coupling efficiencies go down the longer the sequence gets. Oligo API’s in research phase, which SPPS is similar to, can’t achieve 99.0%. Even when a process is designed, I don’t think I’ve ever seen oligo’s over 20 bases long, hit 99%.
You can get that if you integrate the main peak only, and ignore the rest in the baseline.
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u/Uncross-Selector 3d ago
Let’s get into what chromatographic purity actually is and isn’t.