Because supplements are not FDA-approved before sale, third-party testing by independent labs (programs such as NSF, USP, and Informed Sport) is a key quality signal: it verifies the product contains what the label claims, at the stated dose, without meaningful contaminants or banned substances. It does not prove the ingredient works — only that the bottle is what it says.
Also known as
third-party testingNSF CertifiedUSP Verified
Related terms
- Bioavailability
- The share of a dose that actually reaches the bloodstream in active form.