Federal law defines dietary supplements as products that:
- You take by mouth (such as a tablet, capsule, powder, or liquid)
- Are made to supplement the diet
- Have one or more dietary ingredients, including vitamins, minerals, herbs or other botanicals, amino acids, enzymes, tissues from organs or glands, or extracts of these
- Are labeled as being dietary supplements.
Herbal supplements—sometimes called botanicals—are a type of dietary supplement containing one or more herbs.
The amount of scientific evidence on dietary supplements varies widely—there is a lot of information on some and very little on others. If you’re considering using a dietary supplement, it’s important to keep the following in mind:
- Supplements you buy from stores or online may differ in important ways from products tested in research studies.
- Dietary supplements may interact with your medications or pose risks if you have certain medical problems or are going to have surgery.
- Many dietary supplements haven’t been tested in pregnant women, nursing mothers, or children.
- What’s listed on the label of a dietary supplement may not be what’s in the product. For example, some products marketed for weight loss, sexual enhancement, or bodybuilding have been found to contain prescription drugs not allowed in dietary supplements or other ingredients not listed on the label, and some of these ingredients may be unsafe.
- Rules for manufacturing and distributing dietary supplements are less strict than those for prescription or over-the-counter drugs. Although the U.S. Food and Drug Administration (FDA) requires that companies submit safety data about any new ingredient not sold in the United States in a dietary supplement before 1994, the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed.
This publication is not copyrighted and is in the public domain. Duplication is encouraged.
NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.