Dietary Supplements and the Evidence Standard

Separate ingredient research, product claims, and evidence for a finished formula.

An ingredient study does not prove a finished product

Research on a single ingredient may use a different dose, extract, population, duration, or outcome from a commercial product. A trial of magnesium alone does not establish that a multi-ingredient capsule improves sleep. A finished formula needs evidence relevant to its own composition and intended use.

Check the kind of evidence

Animal experiments, laboratory mechanisms, small uncontrolled studies, testimonials, and randomized clinical trials answer different questions. Testimonials cannot show that a product caused the result or predict what another buyer will experience. FTC guidance says health-product advertising must be truthful and adequately substantiated.

Understand FDA oversight

FDA does not approve dietary supplements for safety and effectiveness before they are marketed. Manufacturers are responsible for product safety and lawful labeling. Supplement Facts labels are required to list serving size, dietary ingredients, and amounts per serving. Ask for the actual label when a sales page omits quantities.