# Purity vs Identity on a COA: Don't Confuse the Two

_A COA reports identity and purity separately, and buyers mix them up. What each means and why a high purity number alone can mislead. Educational only._

Source: https://growthguyscanada.coupons/articles/coa-purity-vs-identity.html · Updated: June 17, 2026 · TorontoHealth — educational only, not medical advice.


> **Short answer:** A COA reports two separate things people constantly confuse. **Identity** = is it the right compound. **Purity** = what percentage of the sample is that compound. A 99% pure sample of the *wrong* molecule is still useless.

## Identity, explained

Identity testing confirms the sample is the molecule named on the label. Without it, a purity number is floating free — pure *what*, exactly?

## Purity, explained

Purity is the share of the sample that's the target compound, with the rest being by-products, fragments, or filler. A higher number is better, but only once identity is confirmed.

## The trap of reading one number

Marketing loves a big purity figure because it sounds impressive in isolation. Always pair it with the identity result before you trust it.

Related: [HPLC vs mass spec](/articles/hplc-vs-mass-spec-peptide-testing.html) · [how to read a COA](/articles/how-to-read-a-peptide-coa.html).

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_General educational information, not claims about any specific company. For research and educational purposes only. Not medical advice. Posts may contain affiliate links._