Dietary Supplements

What is a dietary supplement?

In the United States, according to the Dietary Supplement Health and Education Act (DSHEA) of 1994, a dietary supplement is a product intended to supplement (reinforce) the diet, is taken by mouth and contains a “dietary ingredient,” such as minerals, vitamins, amino acids, enzymes, organ tissues, glandulars, herbs or other botanics, or a concentrate, metabolite, constituent, extract or combination of any of the above [1,2].


Dietary supplements can be in the form of tablets, capsules, lozenges, chewables, powders, solutions or syrups. They may also appear as part of foods, for example, nutrition bars.

Nutrient supplements other than dietary supplements are available in the form of skin patches or creams, eye drops, nasal sprays, intravenous and intramuscular injections and rectal suppositories.


  • Natural supplements are extracted from plants, animal tissues or inorganic material, such as seawater and rocks.
  • Semi-synthetic supplements are extracted from natural sources and then chemically changed.
  • Synthetic supplements are completely artificially produced.

Natural or “organic” dietary supplements are not necessary better or safer than synthetic ones.

List of Dietary Supplements

Practically every nutrient can appear as a dietary supplement. Here on Nutrients Review, dietary supplements are described under the related nutrients:

Multivitamin and multimineral supplements and supplements that include various combinations of nutrients, herbal extracts or drugs also exist.

A more complete list of dietary supplements that also includes herb extracts and other substances is here.


Mineral and vitamin supplements can help correct mineral and vitamin deficiencies. If you do not have a nutrient deficiency, you will less likely experience benefits from dietary supplements.

If you are healthy and regularly consume variety of foods, dietary supplements will not likely boost your immunity or help prevent infections or other diseases.

If you have a disease but you do not have a nutrient deficiency, dietary supplements will not likely help you treat that disease. For example, vitamin C or zinc supplements do not likely prevent or shorten the duration of common cold or flu.

Dietary supplements do not likely promote weight loss.


The safety of each supplement is described under a related nutrient. In general, most dietary supplements should be safe when used according to instructions provided by the producers. Most of the side effects result from a supplement overdose.


According to Dietary Supplement Health and Education Act (DSHEA) of 1994, dietary supplements are regulated as foods, not drugs [1,2]. They are producers who are responsible for the dietary supplements’s safety and health claims attached to them, which means they do not need an approval by the U.S. Food and Drug Administration (FDA) before marketing [1,2].

The label of a dietary supplement needs to include [2]:

  • A descriptive name of the product stating that it is a “supplement;”
  • The name and place of business of the manufacturer, packer, or distributor;
  • A complete list of ingredients;
  • The net contents of the product.

FDA does not analyse dietary supplements by consumers’ requests. Consumers can get detailed information about supplements from the producers or private laboratories.

Health Claims

In the U.S., health claims on dietary supplements are made by producers and are, in general, not evaluated by the U.S. Food and Drug Administration (FDA).

FDA is responsible to identify illegal dietary supplements and those promoted by false health claims [2].

If you think you have suffered a serious harmful effect from a dietary supplement, contact your doctor. In the U.S., you can also make a report using Safety Reporting Portal.

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