A certificate of analysis (COA) is a lab report — ideally from an independent third-party laboratory — that describes what a product actually contains. For a peptide vial, a COA typically reports three things: identity (is this the compound the label claims?), purity (often measured by HPLC and shown as a percentage), and mass or content (how many milligrams are present, sometimes confirmed by mass spectrometry). A COA can give you useful information, but it has real limits: it can be faked, it may describe a different batch than the one in your hand, and it can never make an unapproved or unprescribed product safe or legal. This page is educational only and is not medical advice — always confirm with a licensed physician or pharmacist.
A good third-party COA usually covers a few core measurements. Knowing what each one means helps you read the document instead of just trusting a logo at the top.
Remember the unit relationship throughout: 1 mg = 1000 mcg. Mixing these up is one of the most common and dangerous errors people make when reading any lab number.
Two numbers cause most of the confusion: the stated (label) amount and the actual (measured) amount.
These three can disagree. A vial can be over-filled, under-filled, or lower in purity than claimed. A COA is the document that lets you compare the claim to the measurement — but only if the COA genuinely matches your vial.
Example only — these are made-up numbers to illustrate the arithmetic. Your vial may differ; confirm everything with your pharmacist.
Suppose a label states 10 mg, and a COA reports an actual content of 9.5 mg at 98% purity. The amount of intended compound you would actually have is:
This is simple multiplication, not a recommendation. It does not tell you what to take or how much — only what a particular report claims is present. A pharmacist or physician is the right person to interpret what any of this means for you.
One nuance: labs differ in whether the reported "content" is already adjusted for purity, so do not assume you should always multiply content by purity — check how your specific lab defines its numbers.
A COA reduces uncertainty. It does not eliminate it. Treat it as one piece of information, not a guarantee.
For anything you put in your body, the safest path is a licensed pharmacy and a prescription where one is required, and a conversation with your physician or pharmacist.
If someone hands you a COA, a calm, skeptical read goes a long way. A few things worth checking:
Pepathary is a free, offline, educational tracker. It does not sell, source, or recommend any product, dose, or vendor — it simply helps you keep your own records organized.
The app also includes a mixing-math / concentration tool for working out concentration after reconstitution. It is not a dosage calculator and does not tell you what or how much to use; any dosing decision belongs with your physician or pharmacist.
No. A COA reports lab measurements like identity, purity, and content, but it cannot guarantee safety. It can be faked or describe a different batch, and it never makes an unapproved or unprescribed product safe or legal. Discuss any product with your physician or pharmacist.
HPLC (high-performance liquid chromatography) is a lab method that separates a sample into its components. The purity percentage estimates how much of the sample is the intended compound versus impurities. It is one quality indicator, not a complete safety assessment.
The stated mg is the label's claim; the actual mg is what the lab measured. They can differ because a vial may be over-filled, under-filled, or contain lower-purity material. A COA lets you compare the two — but only if it genuinely matches your vial.
You often cannot be certain. Warning signs include no named third-party lab, a missing or mismatched batch number, no date, missing measurements, or a report you cannot independently verify. Treat any unverifiable COA as an unproven claim and ask a pharmacist.
Yes. Pepathary lets you log COA details — batch, lab, stated and measured mg, purity, and a photo — to keep your own records organized and to share clear information with a physician or pharmacist. It does not sell or recommend anything.