Quality & verification

How to read a peptide certificate of analysis.

A COA is the difference between knowing what you have and hoping. Most people never actually read one — here's how, including how to check ours.

The short answer

A certificate of analysis is a laboratory report stating what a product is and how pure it is. To read one properly, check six things: the product name matches what you ordered, the batch number matches the number printed on your vial, the date is recent, HPLC purity is 98% or higher, identity is confirmed by mass spectrometry, and the testing lab is genuinely independent rather than the seller's own bench. HPLC and mass spectrometry answer different questions — purity and identity — so a COA showing only one of them is half a document.

Last updated: August 2026 · For research use only · Not medical advice

Why it matters

Two different things are at stake

The research-peptide market isn't regulated like the pharmaceutical one. Quality varies enormously between suppliers, and nothing about a label guarantees what's inside the vial.

The first thing at stake is money. An under-dosed, degraded or counterfeit product means a research block that produces nothing, plus the cost of buying again properly. People routinely blame a compound for not working when the real problem was that they never had it.

The second is safety, and it's the more serious one. Anything intended for injection has to be sterile and pure. A product carrying endotoxins, contaminants or a different compound than the label claims is a genuine physical risk — and no discount compensates for that.

The base rule is simple: if you can't verify what a substance is and who tested it, you're buying blind. Everything below exists so you don't have to.

The document

Six things to read on any COA

What to checkWhat good looks likeWhat should worry you
[object Object]The exact peptide name, matching what you orderedA vague or generic product description
[object Object]Matches the batch number printed on your vialA COA from a different batch — it tells you nothing about yours
[object Object]Recent, and consistent with the batch you receivedAn old certificate recycled for current stock
[object Object]98% or higher; 99%+ is what you want to seeBelow 95%, or no purity figure at all
[object Object]Mass spectrometry confirming the molecular weight matchesMissing entirely — purity alone doesn't prove what it is
[object Object]An independent third-party lab, named and contactable"In-house analysis" with no external verification

HPLC and MS answer different questions. HPLC measures how pure the sample is; mass spectrometry confirms it's actually the declared peptide. Something can be 99% pure and still be 99% of the wrong molecule — which is why you want both.

Verification

A PDF proves nothing on its own

Any document can be edited in minutes, so the real test is confirming it independently:

  • Find the report number — a genuine COA carries an identifier you can check against the issuing lab's own records or validation system.
  • Verify it at source — use the lab's verification page or QR code where one exists, or email the lab with the report number and ask them to confirm it matches.
  • Cross-check three fields against your vial — product, batch and date. If the batch on the certificate isn't the batch in your hand, the certificate isn't about your product.
  • Treat low-resolution images with suspicion — a blurry screenshot with no lab name and no report number is not evidence of anything.
  • Know the difference between third-party and in-house — an independent lab has no stake in the sale. In-house testing is a useful supplement, but on its own it's the seller vouching for the seller.
The supplier

Signals worth reading

Signs of a serious supplierSigns to walk away from
Third-party testing per batch, published and verifiableNo COA at all, or one generic certificate reused across products
A traceable track record and consistent feedback over timePrices well below the market — usually under-dosed, fake or expired
Transparency about sourcing, shipping and storageUrgency and pressure tactics — "last units", buy now
A clear policy if an order arrives wrong or damagedOnly irreversible payment methods with no recourse
Answers technical questions directly, without dodgingIrritation or silence when you ask for documentation

A supplier who becomes uncomfortable when asked for a batch COA has already answered the most important question.

Five questions

What to ask before you pay

A serious supplier answers all of these without friction — including us:

  • Can you send the third-party COA for this specific batch, with a report number I can verify?
  • Which independent laboratory ran the analysis, and how do I confirm the report myself?
  • What HPLC purity did this batch return, and is identity confirmed by mass spectrometry?
  • Does the batch number on the COA match the one printed on the vial I'll receive?
  • How is it shipped and stored, and what happens if it arrives damaged, discoloured or cloudy?
On arrival

Inspect before you assume

The physical product tells you something too:

  • Vial and seal — the flip-top cap should be intact and unopened, the label legible with name, amount and batch, and the glass free of cracks.
  • The powder — lyophilised peptide is normally a white powder or a compact "cake". In very low-milligram vials there may be barely anything visible, which is expected. A yellow or brown tint, or an oily appearance, is a warning.
  • The clarity check — once reconstituted, the solution should be clear and colourless. Cloudiness that doesn't resolve, visible particles or unexpected colour means stop and contact the supplier.
  • Treat clarity as a check, not a permission slip — a clear solution doesn't prove purity, it just rules out one obvious failure. Most degraded peptides look completely normal.
  • Store it properly from the moment it lands — sealed powder cold, dry and dark; reconstituted solution refrigerated and protected from light. Poor storage undoes good sourcing.
Our position

Apply all of this to us

We publish this guide knowing it will be used to scrutinise us, which is the point. Novapep products are supplied with third-party laboratory analysis, and you're welcome to ask for the certificate covering the batch you're being sent before you commit to anything.

If a supplier — us included — can't produce a batch-specific certificate from an independent lab, that should end the conversation. The whole market improves when buyers ask harder questions, and we'd rather compete on documentation than on being the cheapest option available.

Message us for the COA relevant to your batch, and check it using the six points above.

FAQ

Common questions.

What is a certificate of analysis for peptides?

A COA is a laboratory report stating a product's identity and purity for a specific production batch. It should name the peptide, cite the batch number, show a recent test date, report HPLC purity, confirm identity by mass spectrometry, and come from a named independent laboratory you can contact.

What purity should a peptide COA show?

Look for 98% or higher, with 99%+ being what a good supplier typically returns. Anything under 95% is a warning sign. Bear in mind purity is only half the picture — it tells you how clean the sample is, not whether the molecule is the one you ordered.

What's the difference between HPLC and mass spectrometry on a COA?

HPLC measures purity — what proportion of the sample is the main compound. Mass spectrometry confirms identity by matching molecular weight to the declared peptide. You need both, because a sample can be highly pure and still be the wrong substance entirely. A COA with only HPLC is incomplete.

How do I verify a COA is genuine?

Find the report number and check it directly with the issuing laboratory — via their verification page, a QR code, or by emailing them the reference. Then confirm the product, batch and date on the certificate match what's printed on your vial. A PDF or photo on its own can be edited in minutes.

Is in-house testing good enough?

Not on its own. In-house results are the seller assessing their own product, which is useful as a supplement but not as proof. Third-party testing comes from an independent laboratory with no stake in the sale, which is why it's the standard worth insisting on.

What are the biggest red flags when buying peptides?

No batch-specific COA, one generic certificate reused across products, in-house testing only, prices far below market, "pharmaceutical grade" claims with no documentation, no batch number on the vial, and pressure to pay quickly using methods with no recourse. Any one of these is reason to pause.

This page is educational consumer-protection information and does not constitute medical, pharmaceutical or legal advice, nor a recommendation to use or dose any substance. All products supplied by Novapep are lab-tested and intended for research use only — not for human or veterinary consumption. Check the regulations that apply in your country.

Ask us for the batch COA.

Message us and we'll send the third-party analysis covering the batch you're being supplied.