Product Quality & Contamination

What the sources say

• What is on the label may not be what is in the product. FDA has found prescription drugs, including anticoagulants such as warfarin and anticonvulsants such as phenytoin, in products sold as dietary supplements. [1]
• Products promoted for weight loss, sexual enhancement and bodybuilding may contain prescription drugs not allowed in supplements or other ingredients not on the label; some may be unsafe. [1]
• Some commercial black cohosh products were found to contain the wrong herb or unlisted mixtures. [2]
• A 2012 government study of 127 supplements marketed for weight loss or immune support found 20% made illegal claims. [1]
• Supplements you buy may differ in important ways from products tested in studies. [1]
• "Standardized", "verified" or "certified" does not necessarily guarantee quality or consistency. [1]
• FDA says it cannot test all products that may contain harmful hidden ingredients. [1]

Third-party testing

NIH notes that labels showing testing by independent groups such as the nonprofit US Pharmacopeia (USP) Dietary Supplement Verification Program or ConsumerLab.com can help when judging quality. [3] Testing is voluntary. We do not rank brands or recommend products. A seal does not tell you a product is right for you or safe with your medicines.

Where to check

• FDA's public health alerts about supplements and its Information for Consumers. [4]
• FDA's Dietary Supplement Ingredient Directory. [5]
• NIH's Dietary Supplement Label Database lists the labels of many US products. [1]

Examples of FDA public health alerts

FDA's page links alerts about supplements containing cesium salts, a flax-seed powder and Salmonella contamination, and certain "Life Rising" products. [4] Details change; read FDA's current list.

What to do

1. Buy from sources you can identify and keep the label and lot number.
2. Be most careful with weight-loss, sexual-enhancement and bodybuilding products. [1]
3. Report problems: Side effects and reporting.