How to read a certificate of analysis (COA)
Under FDA's supplement GMP rule, a manufacturer may rely on a supplier's COA for some components only if, among other things, the COA describes the test methods, the test limits and the actual results. [1]
What to look for
A usable COA lists the method used, the limits (specification), and the actual result for each test. [1]
Manufacturers must qualify the supplier by confirming the COA results, document how they qualified the supplier, periodically re-confirm the COA, and have quality control personnel review and approve the qualification documentation. [1]
A supplier's COA can't replace identity testing of a dietary ingredient: manufacturers must run at least one appropriate identity test unless FDA grants an exemption by petition. [1]
How certifiers use it
USP's program tests samples from selected lots against the product's label and certificate-of-analysis claims. [2]
Sources
- eCFR (U.S. Code of Federal Regulations) — 21 CFR Part 111: cGMP for Dietary Supplements retrieved 2026-10-27
- USP — Dietary Supplement Verification Program manual for participants retrieved 2026-10-27