Most counterfeit peptides are caught with five minutes of inspection, not in a lab. This checklist covers the visual, packaging, and CoA tells that flag a bad vial before you ever reconstitute it.
Why visual checks still matter
Lab testing is the only definitive answer, but most outright fakes fail the basics: wrong cap colour, wrong fill, missing batch, sloppy label. A two-minute inspection rules out a meaningful fraction of counterfeit vials before you pay for a CoA.
The vial itself
Fill volume vs labelled mg. 5mg lyophilised peptide should look like a small puff at the bottom of the vial, not a half-full vial of powder. Excessive bulk usually means mannitol-heavy filler.
Colour. Most lyophilised peptides are white or off-white. Yellowing can indicate oxidation or degradation; pink/tan colouring is sometimes a fake-tan / MT-2 substitution tell.
Crimp seal. A loose, off-centre, or scratched crimp seal indicates re-capping. A strong fake signal.
Cake structure. Properly lyophilised peptide forms a fluffy cake. A glassy or melted cake suggests cold-chain failure.
Label and packaging
Batch number printed, not stickered. Real vials have batch codes printed on the label or laser-etched on the glass.
Spelling. "Tirzepetide", "Semaglitide". Typos are common on counterfeit copies of legitimate pharma labels.
QR codes that go nowhere. Scan them. A QR pointing to a Google search or a 404 is a fake.
The CoA
See our full CoA guide for detail, but the quick checks: batch number on CoA must match vial, lab name must be third-party (not the vendor), date must be recent, and both LC-MS and HPLC must be present.
When to send it for testing
If everything looks right but the vendor is new or the peptide is high-value (retatrutide, tirzepatide, tesamorelin), independent testing is the only way to be sure. LabDoc tests a vial for A$549 with a public Certificate of Analysis. See pricing.
Frequently asked questions
Can fake peptides actually hurt you?
Yes: substituted peptides can cause unexpected effects, and contaminated or non-sterile vials can cause infection at the injection site. Identity testing rules out substitution; sterility is a separate test.
How common are fake peptides in Australia?
LabDoc has tested vials labelled as one peptide that came back as something else entirely. Identity failures are not rare in the Australian grey market.
What's the single best fake-spotting check?
Independent LC-MS identity. Visual checks rule out obvious fakes; only lab testing rules out sophisticated substitutions.