Guide · 7 min read

How to tell if a peptide COA is fake

By the PeptideCOACheck team · Last updated November 2, 2026 · How we check

A Certificate of Analysis (COA) is the main evidence a research-peptide seller offers that a vial contains what the label says. It is also easy to fake. This guide is a verification workflow: seven checks, in order, that move a COA from "looks fine" to "confirmed by the lab". For a quick list of warning signs, see COA red flags.

Get the full, original document

Start by asking for the complete report as the lab issued it, usually a PDF, not a cropped screenshot on a product page. A full report normally has a header with the lab's name and contact details, a sample or task number, the sample description as submitted, test dates, each method used, the results, and some form of sign-off or verification code. Every missing section is a missing chance to check something.

A seller who only offers a cropped image, or says the full report is "confidential", isn't proving anything is fake. They are asking you to trust them without evidence, so weigh the document accordingly.

Match the document to your vial

A genuine COA for a different batch is, for practical purposes, not your COA. Compare:

• Product name: the compound on the report matches the label, including the form (for example, acetate versus free base, or a copper complex such as GHK-Cu).
• Batch or lot number: the number on the report matches the number on the vial or packing slip, exactly.
• Stated amount: if the report measured content, it should be in line with the label (for example, a "10 mg" vial measured at about 10 mg).
• Date: the test date is recent and after the batch could have been made. A date in the future is a hard fail.

Many fake COAs are real reports that have simply been reused for a newer batch. Batch matching catches that.

Inspect the file itself

Zoom in on the key numbers: purity, mass, batch and date. Edited documents often give themselves away through:

• Fonts, sizes or weights that differ from the surrounding text, especially on the numbers that matter most.
• Values that are sharper or blurrier than the rest of the page, or sit slightly off the baseline.
• White boxes, smudges or compression blocks around a figure.
• A chromatogram or spectrum that is a low-resolution image pasted into an otherwise crisp PDF.

If you have the PDF, the document properties (creator application and modification date) can be informative. A lab report "modified" by an image editor weeks after it was issued deserves a question. None of these is proof on its own, because legitimate reports get re-exported too, but each is a reason to move on to lab verification.

Check that the science adds up

Forgers often get the layout right and the chemistry wrong. A few quick checks:

• Mass: the mass-spec result should match the compound's theoretical molecular weight within about ±1 Da (or 0.03% for large peptides), or match a charge-state ion such as [M+2H]²⁺. A mass that belongs to a different peptide is a serious problem. See mass spectrometry explained.
• Purity: a value above 100% is impossible, and an exact 100.0% is unusual for a real chromatogram. See what a good HPLC purity is.
• Internal consistency: the purity in the summary matches the peak table, and the main peak's area percentage matches the stated purity.
• Method details: real HPLC results usually state the column, wavelength and gradient. "HPLC: 99.5%" with nothing else is thin evidence.

The free COA checker runs these checks for you, including charge states and look-alike compounds, and explains each result.

Compare across batches and products

If a seller publishes many COAs, put a few side by side. Identical chromatograms (same peak shape, same tiny shoulders, same baseline noise) on reports for different batches or different compounds are a classic sign of recycled data. So is the same report number or test date on "different" reports. Every product from one seller at exactly 99.9% isn't impossible, but it is worth noticing.

Verify the report with the lab

This is the check that actually confirms a COA. Many independent labs give each report a unique identifier and offer a way to confirm it:

• An online lookup. For example, Janoshik Analytical, a lab widely used for research-peptide testing, has a verification page where you enter the task number and a unique key printed on the report, or scan the report's QR code. Its help center explains that a report is only legitimate if it matches the version stored in the lab's system.
• A QR code that opens a page on the lab's own domain. Check the address carefully. A QR code pointing to the seller's website, or to a look-alike domain, verifies nothing.
• Email confirmation. If there is no portal, email the lab using contact details from the lab's own website (not the PDF, and not the seller) and ask whether it issued a report with that number, date, sample name and result.

Compare what the lab shows you with the document you were given, line by line. A verified report with a different purity, mass or sample name than the one shown on the product page is itself a red flag.

Confirm the lab is independent and real

Finally, check who the lab is. Does it have its own website, a physical address and a history of reports that others have verified? Is it independent of the seller, or is "Lab Analysis Dept." just another page of the store? In-house testing isn't automatically dishonest, but it is the seller grading its own work. See third-party peptide testing labs explained.

Putting it together

Educational content only. Not medical advice. Lab names are examples to illustrate how verification works, not endorsements. Research peptides are sold for laboratory research purposes only.