---
title: "Peptide COA Purity Testing: Why the Numbers Lie"
description: "Peptide COA purity numbers vary wildly by lab method. See why the same vial tested at three labs returned 91%, 94%, and 97.8% — and what that means."
canonical: "https://www.vitalsvault.com/blog/peptide-coa-purity-testing-lab-variation"
last-updated: 2026-08-22
---

# Peptide COA Purity Testing: Why the Numbers Lie

> Peptide COA purity numbers vary wildly by lab method. See why the same vial tested at three labs returned 91%, 94%, and 97.8% — and what that means.

---

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