The Food and Drug Administration (FDA) requires the makers of supplements to follow what it calls "good manufacturing practices," or GMPs. But some supplements carry “seals of approval” from independent certification programs, which claim to keep tabs on the supplements industry. These include:
ConsumerLab.com. The best known certification program comes from this private company, which has analyzed thousands of products in most popular supplement categories. ConsumerLab.com randomly buys products from stores, from catalogues, over the Internet or through multilevel marketing companies and coordinates their testing at independent labs. The labs test for identity of ingredients, strength, contamination and ability to disintegrate. If a product passes muster, it can then, for a licensing fee, display the ConsumerLab. com “Approved Product Quality” seal on its label and in advertising, subject to periodic retesting. Manufacturers may also pay to have their products tested under ConsumerLab.com’s Voluntary Certification Program.
The U.S. Pharmacopeial Convention (USP). This nonprofit organization, which sets standards for drug manufacturers, also certifies supplements that pass testing under its Dietary Supplement Verification Program. For a fee, manufacturers can have products analyzed for accuracy of labeling, purity and speed of disintegration. USP, unlike ConsumerLab, tests more than the finished product; it also makes sure the supplement is made according to good manufacturing practices. If it passes testing (and random retesting) and an on-site manufacturing plant audit, the product may display the “USP Verified” seal. In contrast, the older USP seal, consisting of the initials “USP,” simply indicated that the manufacturer voluntarily met USP’s requirements; no one checked on compliance.
NSF International. This nonprofit organization, best known for certifying bottled water and water filters, also evaluates supplements under its voluntary certification and testing program. Products made under good manufacturing practices, with accurate ingredient labels and no contaminants, may display the NSF seal. Testing is done, for varying fees, in NSF’s own accredited labs.
Certification programs help ensure that a supplement contains what it claims, without impurities. But they have limitations, such as these:
- There is debate about the testing methods used, which can vary from lab to lab. If a product passes in one lab, it may not pass in another. Companies may test samples from only a few lots, or even just one lot. However, different lots can vary widely in quality and purity.
- Products that fail are not always identified. If a product doesn’t meet testing standards, nothing on its label will warn you.
- Products without seals are not necessarily inferior. They simply may not have been tested.
- The seals don’t address the big questions: Is the product safe—and does it work? While the seals are evidence of passing tests for manufacturing quality, they are not proof of safety or efficacy. The supplements may still interact with certain drugs, be dangerous if you have certain medical conditions and/or have unexpected side effects and unknown long-term effects.