The Dietary Supplement Health and Education Act, enacted by Congress in 1994, defines a supplement as a substance meant to fortify the diet and contains a herb, amino acid, vitamin or mineral, or a combination, or a concentration of ingredients. Supplements are intended to be ingested in the form of a tablet, liquid, pill, powder or capsule, are not considered food and are labeled as dietary supplements. Furthermore, the ingredients used in supplements are typically only food-grade. They are usually sourced from a third party, and they normally receive little or no testing to ensure safety, quality, potency or purity. With many supplements, particularly vitamins and minerals, inferior forms of the substances are used, resulting in poor bioavailability (the ability to be absorbed).
Nutraceuticals are defined as a kind of supplement that provides a concentrated source of biologically active ingredients from foods that are supplied in a non-food form. These products are intended to improve overall health and are formulated in dosages much higher than those found naturally in the diet. Some nutraceuticals are intended to treat or prevent a variety of health problems and chronic diseases or to increase physical performance. They use pharmaceutical grade (USP) ingredients and undergo rigorous testing for safety, purity, potency and quality, and the ingredients may be produced on-site by the same company or sourced from elsewhere with great care. Because of their superior potency and high dosages, they are typically only provided by licensed physicians.