The US Pharmacopeia (USP) verifies the quality, purity, and potency of dietary supplements for companies that take part in their certification program. Supplements that display the “Dietary Supplement USP Verified” mark on labels have been tested to verify that they dissolve properly. (Vitamin and mineral supplements that don’t carry the USP symbol may still be of high quality; it just means they haven’t been certified.) Other independent organizations that offer similar guarantees are ConsumerLab.com and NSF International.
