Peptide Footnotes

The claim

99% purity on the certificate means the vial is good to use
Mixed

Some real evidence, with clear limits or conflicts.

Evidence strength3/5

How to Read a Purity Certificate

Filed 23 Oct 2026 · Last reviewed · 1 min read · 3 reads

Purity is one number from one test. It does not cover identity, sterility, endotoxin or whether the lab is real.

What the claim says

A chromatogram showing "99%" is presented as proof that the product is ready for use.

What purity can tell you

HPLC purity measures what fraction of the detected material is the main peak. Combined with mass spectrometry, it supports the idea that the right molecule is present.

What it cannot tell you

  • Whether the sample tested is the sample you received.
  • Sterility, endotoxin levels or solvent residue.
  • The actual amount in the vial.
  • Whether the certificate is genuine.
Purity is a necessary clue, never a sufficient one.

Verdict

Mixed. A real, independent certificate is useful. A PDF supplied by the seller proves little.

Bottom line

  • Look for third-party testing tied to a batch number.
  • Identity (mass spec) matters as much as purity.
  • A good number on a bad test is still a bad test.

Educational only. Not medical advice. See the disclaimer.

Neighbouring files

No. 35Buying & Labels Weak "Research use only" peptides are as safe as regulated products What "Research Use Only" Actually Means 1/51 min read No. 34Buying & Labels Weak Swallowed peptide capsules deliver the same effect as injections Do Oral Peptide Supplements Survive Digestion? 2/51 min read No. 09Buying & Labels Weak A peptide dosing chart can tell you how much of any peptide to take Peptide Dosing Chart and Cheat Sheet Built Only From Approved Labels 2/57 min read