FDA regulates both finished dietary supplement products and dietary ingredients. FDA regulates dietary supplements under a different set of regulations than those covering "conventional" foods and drug products. Under the Dietary Supplement Health and Education Act of 1994 (DSHEA):

Manufacturers and distributors of dietary supplements and dietary ingredients are prohibited from marketing products that are adulterated or misbranded. That means that these firms are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all the requirements of DSHEA and FDA regulations.

FDA is responsible for taking action against any adulterated or misbranded dietary supplement product after it reaches the market.

This section provides detailed information about:

Products & Ingredients Information on selected dietary supplement products, ingredients, and other substances.

Information for Consumers Tips for dietary supplement users, including older supplement users.

Information for Industry Resources and links for applications, forms, guidance, and other items of interest to industry members.

Report an Adverse Event Learn how consumers, health care providers, and others can report a complaint, concern, or problem related to dietary supplements. Includes links to guidance for dietary supplement manufacturers, packers, and distributors.

New Dietary Ingredients Notification Process Background information for industry, instructions for submitting premarket notifications, and links to relevant guidance and Federal Register documents.

Continue reading here:

Dietary Supplements - Food and Drug Administration