To verify a peptide COA, open the report on the testing lab’s own website, not the seller’s PDF. Then confirm the numbers match, the lot number matches your vial, and the sample wasn’t hand-picked. Check that identity, purity and content were each tested. Endotoxin and sterility are separate tests, and a purity number covers neither.
Last checked: October 10, 2026. Research use only. Not medical advice.
Here is why a COA alone isn’t proof. Vanguard Laboratory says a certificate carrying its name was a complete forgery, and the retatrutide report on it referenced a different drug, tirzepatide. In a 2024 JMIR test-purchase study, one vendor’s paperwork claimed 99% purity, while semaglutide made up 7.70% of the powder mass measured. More cases are in our fake peptide vendors list.
The 7 COA checks at a glance
| # | Check | What passes | Red flag |
|---|---|---|---|
| 1 | Find the report at the lab | Report ID opens on the lab’s own domain, and the lab is accredited for the test | PDF only on the seller’s site, no lookup, lab can’t be reached |
| 2 | Compare the results | Seller’s PDF and lab record match digit for digit | Different purity, mass, date or client name |
| 3 | Match product and lot | Same compound, strength and lot number as your vial | No lot number, an old date, or a different compound |
| 4 | Ask how the sample was chosen | Documented sampling from finished inventory | Seller picked and sent one vial |
| 5 | Know what each test covers | Separate identity, purity and content results; endotoxin and sterility if claimed | “99% purity” offered as the whole story |
| 6 | Read the details | Method, units, sample description and full result pages | Certificate graphic only, QR code to a non-lab domain |
| 7 | Treat gaps as gaps | Every link above holds | Any missing link, explained away |
1. Find the original report at the laboratory
Start with the report number, task ID, QR code, or verification key printed on the COA. Type the laboratory’s address into your browser yourself, then use its report lookup. Don’t rely on a PDF hosted only on the seller’s website.
For example, Janoshik has a public verification page where you can enter report identifiers and open the lab’s record. Verify a result through Janoshik.
A vendor-hosted PDF can be edited or replaced. That doesn’t prove the seller changed it. It means the PDF alone doesn’t prove the laboratory issued those exact results. If the lab offers no lookup page, contact it using details you find independently and ask whether it issued the report number.
Then check the lab itself. ISO/IEC 17025 is the standard for testing-lab competence, and accreditation covers named tests, not the whole lab. Ask which accreditation body issued it, and look the lab up in that body’s directory. ILAC’s signatory search lists recognised accreditation bodies. A lab without accreditation isn’t automatically wrong, but its results carry less weight. Our Unyx Peptides review shows what that looks like: real lab-hosted certificates from a lab with no ISO/IEC 17025 accreditation.
2. Compare the results, not just the purity headline
Put the vendor’s PDF beside the laboratory’s record. Compare the peptide name, reported purity, measured content, identity result, sample description, test date, report number, and client or submitter field, if shown.
Check the numbers digit for digit. A rounded number in marketing copy may be harmless, but a different result on the seller’s PDF and the lab’s record needs an explanation from the lab.
Save the original lab page or report with the date you checked it. If the records disagree, don’t guess which one is current. Ask the laboratory to confirm the valid report. Until then, treat the result as unverified.
3. Match the report to the product and lot
A real report can still be irrelevant to your vial. Check that the compound, salt form, strength or sample description, and lot or batch number match the product being represented.
This happens. When we checked Selank and Semax vendors, one product page linked a certificate for Oxytocin 5 mg. The report was real. It just wasn’t for the product on sale.
Compare the lot number printed on your vial or package with the number on the report. If the report has no lot number, ask the seller how the tested sample connects to the lot being sold. A product name alone doesn’t establish a batch match.
Then check the test date. An older report may describe an earlier batch. It can’t verify a newer lot just because the product name stayed the same.
4. Ask how the sample was selected
A laboratory tests the material submitted to it. The report doesn’t automatically prove that every vial in a batch, or the vial you received, is identical to that sample.
Ask who selected and sent the sample. Was it randomly drawn from finished inventory, or chosen by the seller? Was it taken from a sealed vial? Is there a documented link between the tested sample and the batch offered for sale?
If the seller picked the sample, selection bias is possible. A clean result from one hand-picked vial can’t establish the contents of every vial. A report is stronger when sampling is documented and the lot connection is clear. It still doesn’t test the specific vial you have unless that vial itself was tested.
5. Know what each test can tell you
HPLC purity estimates the proportion of detected material represented by the target peak under that method. It doesn’t, by itself, tell you the total amount of peptide in the vial.
Identity testing, often by mass spectrometry, checks whether the measured mass is consistent with the claimed compound. Content or net-peptide testing addresses how much peptide is present. Purity and content answer different questions, so look for separate methods and results. Don’t let “99% purity” stand in for both. The JMIR study above is the clearest example: a 99% purity claim, and 7.70% of the powder mass was semaglutide.
Endotoxin and sterility are their own tests. Endotoxin is usually reported in endotoxin units (EU) per mg or per mL, measured with the bacterial endotoxins test in USP chapter <85>. FDA’s pyrogen and endotoxins testing Q&A explains how those limits are set. Sterility testing is USP chapter <71>. If a product page shows a “sterile” or “endotoxin tested” badge, the COA should show the result, the method, and the limit it was judged against. Across the 53 Unyx reports we tracked, none carried a usable endotoxin result, while the product pages displayed sterility badges.
Check what the report doesn’t test, too. HPLC purity alone doesn’t establish sterility, endotoxin levels, residual solvents, or safety for human use. A COA can only support the claims it actually reports. For a side-by-side comparison, see our guide to the best peptide vendors, compared by COAs and endotoxin evidence.
6. Inspect the details behind the number
Look for the method and units, then check the sample description, test date, and report identifier. Read the actual result pages, not just a certificate graphic.
A polished logo or a QR code isn’t proof. The code should lead to the laboratory’s official domain, and the result there should match the document. If the report shows only a summary, ask for the complete report or ask the lab what the listed method measured.
For comparison, every NextGen certificate we opened in our audit of 171 NextGen Peptides COAs was a full panel: HPLC purity, identity, heavy metals, sterility and endotoxin, filed by lot. The weak point there was check 1: the PDFs are vendor-hosted.
7. Treat gaps as gaps
No lookup or lot match means you lack verification. A mismatched result or unexplained sample source does too. That doesn’t automatically prove fraud. It means the COA can’t support the claim being made.
A COA is evidence about a tested sample. It isn’t a guarantee about every vial, and it doesn’t prove that a research-use product is approved or safe for people. The Mississippi Board of Medical Licensure states that research-grade peptides are not FDA-approved and have not been determined safe or effective for human use. Board statement on research-grade peptides.
Verify the record at the lab. Match it to the lot. Know what was tested. If one link is missing, the headline purity number isn’t enough.
Peptide COA questions
How can you tell if a peptide COA is fake?
Look the report up on the testing lab’s own website using the report number or QR code, and compare it digit for digit with the seller’s PDF. A report the lab can’t find, a QR code that leads somewhere other than the lab’s domain, or a result that names a different compound are all signs the document can’t be trusted.
What should a peptide COA include?
A lab name you can verify, a report number, a test date, the lot number, and separate results for identity (usually mass spectrometry), purity (usually HPLC) and content. If the seller claims the product is sterile or endotoxin tested, the COA should show those results, the method and the limit used.
Does 99% purity mean the vial contains 99% peptide?
No. HPLC purity is the share of detected material in the target peak. It doesn’t measure how much peptide is in the vial. In a 2024 JMIR test purchase, paperwork claimed 99% purity while semaglutide made up 7.70% of the powder mass.
Is a vendor’s COA enough to trust a peptide?
No. A COA describes the sample that was tested. It only supports your vial if the report is confirmed at the lab, the lot number matches, and the sample was drawn fairly. It never shows that a research peptide is approved or safe for human use.
Sources
- Ashraf AR, et al. Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription. J Med Internet Res. 2024;26:e65440.
- Vanguard Laboratory. When the paper lies: exposing fake COAs in the peptide market.
- U.S. FDA. Guidance for Industry: Pyrogen and Endotoxins Testing, Questions and Answers.
- ISO. ISO/IEC 17025:2017, General requirements for the competence of testing and calibration laboratories.
- Mississippi State Board of Medical Licensure. Statement on research-grade peptides.