Dietary Supplements

The majority of adults in the United States take one or more dietary supplements either every day or occasionally. Today's dietary supplements include vitamins, minerals, herbals and botanicals, amino acids, enzymes, and many other products. Dietary supplements come in a variety of forms: traditional tablets, capsules, and powders, as well as drinks and energy bars. The Food and Drug Administration is the federal agency that oversees both dietary supplements and medicines.

Use of dietary supplements

Dietary supplements are intended to supplement and not promote the sole source of the vitamin or mineral.  They are not intended to treat, diagnose, prevent or cure disease.  Dietary supplements can be a part of one's health maintenance routine when included after discussions with one's health care treatment team. 

FDA: the difference between medicine and dietary supplements 


  • Medication must be approved by the FDA before it can be marketed.

Dietary Supplement

  • Dietary supplements do not require premarket review or approval by the FDA.
  • Dietary supplement companies do not have to provide evidence of safety to the FDA before the product is marketed.
  • While the supplement company is responsible for having evidence that their products are safe and the label claims are truthful and not misleading, they do not have to provide that evidence to the FDA before the product is marketed.


  • Dietary supplement companies are allowed to make health claims however, that does not mean that the claim has been evaluated or approved by the FDA.  Any supplement that makes a health claim must include the disclaimer, "This statement has not been evaluated by the U.S. Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease."
  • Be aware that an herbal supplement may contain dozens of compounds and that all of its ingredients may not be known.
  • Analyses of dietary supplements sometimes find differences between labeled and actual ingredients. For example:
    • An herbal supplement may not contain the correct plant species.
    • The amounts of the ingredients may be lower or higher than the label states. That means you may be taking less-or more-of the dietary supplement than you realize.
    • The dietary supplement may be contaminated with other herbs, pesticides, or metals, or even adulterated with unlabeled, illegal ingredients such as prescription drugs- See production below
  • Companies may claim "proprietary blends" of herbals.  This means the blend is protected by law or is considered a "trade secret" and therefore does not need to be disclosed on the label as it relates to amounts of elements in the blend.  This makes it hard for the consumer assess safety and determine use indicators. 
  • The term "natural" doesn't always mean safe. A supplement's safety depends on many things, such as its chemical makeup, how it works in the body, how it is prepared, and the dose used.


  • The FDA has established quality standards for dietary supplements to help ensure their identity, purity, strength, and composition. These standards are designed to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture dietary supplements.
  • Several independent organizations offer quality testing and allow products that pass these tests to display their seals of approval. These seals of approval provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. These seals of approval do not guarantee that a product is safe or effective. Organizations that offer this quality testing include:
    • U.S. Pharmacopeia
    • NSF International



Source:  National Institute of Health, National Center for Complementary and Integrative  Health