How to Read Peptide Lab Results: COA Warning Signs and the Finnrick Rows on Our COAs Page
A certificate of analysis connects a laboratory result to the powder from one particular batch. The basics take about ten minutes to pick up. This guide opens with the warning signs, explains each section of a typical certificate, and then reads the Finnrick results on our own COAs page the same way, gaps included.
Five warning signs, most serious first
- The certificate has no batch number, or its batch differs from the one on the vial.
- No independent laboratory is named. Testing done in-house is not third-party evidence.
- Purity is stated, but no chromatogram or method details back it up.
- Only HPLC was run, with nothing from mass spectrometry to confirm identity.
- A single old certificate is being used for a product that has sold continuously for years.
Contaminant results
Endotoxin. Fragments of bacterial cell walls can throw off biological assays even in trace amounts, and purity is no protection: a 99.9% pure peptide can still carry a meaningful endotoxin load. Labs measure it with the limulus amebocyte lysate (LAL) assay, reporting endotoxin units (EU) per mg or per mL against a stated threshold. “PASSED” next to a stated limit is acceptable, and a numeric result is better still.
Heavy metals and sterility. An ICP-MS screen looks for lead, mercury, arsenic and cadmium that raw materials or equipment might introduce. A sterility test checks the lyophilized product for viable microbes. Long-duration studies, where contaminants accumulate, are where both matter most.
Mass spectrometry: is it the right molecule?
Purity and identity are separate questions. Mass spec answers the second by checking the measured molecular weight against the target sequence, about 1419 Da in the case of BPC-157, and the observed value should fall within roughly a dalton of theoretical. A certificate with both MS and HPLC on it is the standard for showing identity and purity together.
HPLC: how clean is it?
Chromatography separates what is in the vial into peaks, and the purity number is the share of total peak area belonging to the target peptide. A reading of 99.4% therefore means 99.4% of detected material was the intended peptide; truncated sequences and synthesis by-products usually make up the remainder. On the chromatogram, check for a single dominant peak, a stated retention time and the wavelength used, typically 214 or 220nm. Be wary of a round figure with no chromatogram, since real results look more like 99.42%.
The header: batch, date and lab
The top of the certificate should say exactly what was tested: the peptide’s name, a batch or lot number, the date of testing and the lab responsible. The batch number matters most, since it should be identical to the one printed on your vial. Without one, or with one recycled across many batches, the certificate decorates rather than documents.
Reading the Finnrick results on our COAs page
Our COAs page lists third-party tests of Welon Peptide Solutions products by Finnrick, a testing service that buys samples or receives them through its testing programs and publishes each result. Every row has four parts: the product, the test date, the result, and a link to Finnrick’s certificate for that test. Three real rows from the page:
| Product | Test date | Result |
|---|---|---|
| Retatrutide | 26 Jun 2026 | Pass · Purity 99.7% |
| GHK-Cu | 6 Dec 2025 | Pass · Purity 99.86% |
| TB-500 (Thymosin Beta-4) | 9 Aug 2026 | Pass · Purity 99.6% |
The page currently lists 31 passed tests across six products: Retatrutide (12), GHK-Cu (6), BPC-157 (5), Tirzepatide (4), TB-500 (Thymosin Beta-4) (2) and HGH 191AA (Somatropin) (2). Test dates run from 23 Nov 2025 to 9 Aug 2026, and reported purity ranges from 99.5% to 99.9%. Read each row as: Finnrick tested a sample of this product on this date, it passed, and this is the purity it reported.
What those rows don’t tell you
- Whether every test passed. The page shows passed tests only. Finnrick publishes the full history for each product, linked under it, and that history can include other results.
- Anything about your vial’s batch. The rows carry no batch number, and each result applies only to the sample tested. Hold our page to the first warning sign above and this is where it falls short: these results are product-level evidence, not a match to the vial in your hands.
- Which strength was tested. A row names the product, not the vial size.
- Contaminants. The rows show a pass and a purity figure. They show no endotoxin, heavy-metal or sterility result, so don’t read one into a pass.
- Identity and method. A purity figure alone doesn’t establish identity. Open the linked certificate and look for a mass-spec result, a chromatogram, a retention time and a wavelength, then weigh the number by what you find there.
- The lab. Our page names Finnrick but not the laboratory that ran each analysis.
- Most of the catalog. Products outside those six, semaglutide and sermorelin among them, have no Finnrick result on our page.
On the last warning sign the page fares better: Retatrutide alone has 12 passed tests spread from February to June 2026, rather than one aging certificate. For research use only. Not for human or veterinary use. The purity percentage guide goes further into HPLC.
