What's in the Bottle? An Introduction to Dietary Supplements

Written by National Center for Complementary and Alternative Medicine

Detailed information on dietary supplements - what they are, how they're used, and safe use of dietary supplements.

On this page

• Introduction
• Questions and Answers
• Definitions
• For More Information
• References

Introduction

Dietary supplements are a topic of great public interest. Whether you are in a store, using the Internet, or talking to people you know, you may hear about supplements and claims of benefits for health. How do you find out whether "what's in the bottle" is safe to take and whether science has proven that the product does what it claims? This fact sheet provides some answers.

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Questions and Answers

1. What are dietary supplements?
2. Why do people take supplements?
3. Is using supplements considered conventional medicine or complementary and alternative medicine (CAM)?
4. How can I get science-based information on a supplement?
5. If I am interested in using a supplement as CAM, how can I do so most safely?
6. I see the word "natural" on a lot of supplement labels. Does "natural" always mean "safe"?
7. Does the Federal Government regulate supplements?
8. Is NCCAM supporting research on supplements?

1. What are dietary supplements?

Dietary supplements (also called nutritional supplements, or supplements for short) were defined in a law passed by Congress in 1994 (see the box below).^{1, 2}

Dietary Supplements...

• Are taken by mouth.
• Contain a "dietary ingredient" intended to supplement the diet. Examples of dietary ingredients include vitamins, minerals, herbs* (as single herbs or mixtures), other botanicals, amino acids, and dietary substances such as enzymes and glandulars.
• Come in different forms, such as tablets, capsules, softgels, gelcaps, liquids, and powders.
• Are not represented for use as a conventional food or as a sole item of a meal or the diet.
• Are labeled as being a dietary supplement.

* Linked terms are defined at the end of this fact sheet.

Dietary supplements are sold in grocery, health food, drug, and discount stores, as well as through mail-order catalogs, TV programs, the Internet, and direct sales.

References