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Peptide COA Red Flags: Ten Things to Check and What to Do

Published October 2026 · 7 min read

No single item here proves a document is fake or a product is bad. Treat them as prompts to ask a question. One may have an innocent explanation; several together are a reason to stop and verify before relying on the material.

1. No laboratory is named

A COA with a generic header and no lab name, address or contact cannot be checked. Ask: which lab produced this, and how can I confirm it? (See how to check that the lab is real.)

2. The same chromatogram appears for different products or lots

Real chromatograms have noise, baseline drift and small peaks that differ from run to run. If two different products show peaks that match down to the baseline wiggles, one image is being reused. Ask: can I see the raw data file for this specific lot?

3. Every result is suspiciously uniform

If every compound, in every lot, reports exactly the same round purity, be curious. Real synthesis varies by sequence and by run, and honest paperwork reflects that. Ask: how many lots have you tested, and can I see a few?

4. No lot or batch number, or one that doesn't match the vial

The lot on the document should be the lot printed on what you received. Ask: which lot is this report for, and where is it printed on the vial?

5. Purity only — no identity confirmation

HPLC alone says how clean something is, not what it is. A report with no mass spectrometry or other identity method has answered half the question. (More in HPLC vs. LC-MS.)

6. The observed mass doesn't fit the compound

The measured mass should sit close to the theoretical mass for the compound, within a fraction of a dalton on a good instrument and within about a dalton at worst on a basic one. Charge-state peaks (for example [M+2H]2+) need to be converted before comparing. Ask: what charge state is shown, and what is the theoretical mass you're comparing against?

7. The dates don't make sense

An analysis date before the material could have been made, a date after the sale, or dates that differ between pages all deserve a question. Ask: when was this lot manufactured and when was it tested?

8. It's an image of a document, not the document

Low-resolution screenshots, mixed fonts, text that doesn't align, or pasted-in graphics can point to editing. A legitimate lab report is normally a clean PDF. Ask: can you provide the original PDF direct from the lab?

9. The paperwork covers a different product

A COA for a different strength, a different salt form, or a slightly different compound name does not document what you bought. Ask: does this report cover the exact product and strength on the order?

10. There is a purity claim but no document

">99% purity, lab tested" in marketing copy with nothing to open is just a sentence. Ask: where is the report that supports this?

If several flags appear: ask the supplier your questions in writing and note how they respond. A clear, specific answer is a good sign; vagueness or silence is information too. For work where the identity or amount really matters, an independent analytical check of your own sample is the only direct way to know.

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