Dietary Supplements

Nutrition & Health Info Sheets for Consumers - Herbal and Dietary Supplements

Nutrition & Health Info Sheets contain up-to-date information about nutrition, health, and food. They are provided in two different formats for consumer and professional users. These resources are produced by Dr. Rachel Scherr and her research staff. Produced by Jessica Fung, Amber Morris, Alexandra Gori, Guadalupe Ambriz, Britt Loofbourrow, PhD Candidate, Anna M. Jones, PhD, and Rachel E. Scherr, PhD.

What Are Herbal and Dietary Supplements?

Herbal and dietary supplements are over-the-counter products taken to support health or wellness. For a product to be defined as an herbal and dietary supplement, it needs to meet a set of definitions:

  • It needs to have the intention to supplement the diet and contain one or more dietary ingredients (vitamins, herbs, minerals, botanicals, or amino acids);
  • It needs to be taken by mouth in the form of a pill, capsule, tablet, or liquid substance; and
  • The label needs to include that it is a dietary supplement [1].

How Common Are Herbal and Dietary Supplements?

Over half of Americans report using dietary supplements with the intended goal to promote overall wellness [2]. The most used include multivitamin-multimineral supplements, vitamin D, and omega-3 fatty acids [2].

What are the Recommendations for Herbal and Dietary Supplement Use?

According to the Dietary Guidelines for Americans 2020-2025 supplements can help people meet dietary needs if this isn’t possible through food and beverages [3]. However, supplements are not meant to be used in place of a healthy diet [4].

Examples of cases where supplements may help:

  • Vitamin D: Vitamin D is only found in a few foods. Humans can make vitamin D in the skin with enough sun exposure. However, in some cases, sun exposure may be limited due to location, climate, or sunscreen use [3].
  • Iron: Many people do not consume enough iron. Groups who may need an iron supplement to meet recommended amounts include teenaged girls and pregnant women [3].
  • Folate (Folic Acid): Folate, one of the B vitamins, has been added to grain products in the US since 1998. This vitamin decreases the risk of a type of birth defect, known as neural tube defects. Women of child-bearing age should consume 400 mcg of synthetic folic acid from fortified foods and/or supplements [3].
  • Omega-3 Fatty Acids: Omega-3 fatty acids, which can be found in fish oil supplements, may help for people with heart disease [4, 5].

Talk to a doctor when using any supplement to know how much to take, how long to take the supplement, and whether it might interact with other supplements or medications, and any other concerns [4].

Are the Claims on Herbal and Dietary Supplements True?

Supplement labels can’t say a product treats or prevents a disease. Labels are allowed to make two types of claims:

  • Qualified health claims, which explain how the supplement may be important for health, or
  • Structure-function claims, which describe how the product affects the structure or function of the body [4-6].

A qualified health claim notes the connection between an ingredient in the supplement and the decreased risk for disease or condition. A health claim must be approved by the FDA [4].

A structure-function claim describes how the ingredient supports the body’s normal role. An example of this is “Calcium builds strong bones.” It does not state the supplement can be used as a treatment or cure and only states the body’s normal role [5].

Supplements can be advertised using a variety of platforms including TV commercials, packaging, and internet ads, among others [7]. The use of social media has been increasing as “influencers” advertise to their fan bases [7]. The Federal Trade Commission (FTC) controls any type of advertisement and ensures that there are no misleading claims that are advertised. If there are misleading statements or the product does not state side effects, consumers are advised to inform the FDA (1-800-332-1088) and FTC ( so the product can be removed from the market [8].

Many companies use vague claims because of how strict requirements are for health and structure-function claims [9, 10]. Due to the vague claims, all consumers should speak to their health care provider about the benefits or damaging effects of using supplements.

What are the Dangers of Using Herbal and Dietary Supplements?

Consumers may not consider that there may be risks in taking dietary supplements. Risks in taking supplements include sudden adverse consequences and unexpected interactions with medications. Due to minimal regulations in the supplement industry, supplements are regulated differently than food or medications. Supplements do not have to be proven safe before they are sold [1]. When supplements are found to be unsafe, the FDA can remove the product from the market.

There are other organizations that test supplements to verify that the advertised ingredients are present in the supplement and there are not any additional ingredients. These include NSF International and US Pharmacopeia (USP) [13,14]. However, these organizations do not verify that the supplement can do what it claims to do.    

Discussion of supplement use with a doctor is strongly encouraged for all consumers, but especially for those who are already taking medications [4]. Some supplements can interact with medications, make medications less effective, or cause unexpected side effects. Users of supplements are advised to discuss with health professionals before taking supplements to avoid further health complications.


  1. Commissioner O of the. FDA 101: Dietary Supplements. FDA. Published online September 9, 2020. Accessed July 19, 2021.
  2. Mishra S, Potischman N. Dietary Supplement Use Among Adults: United States,. 2021;(399):8.
  3. Dietary Guidelines for Americans, 2020-2025. :164.
  4. Dietary Supplements: What You Need to Know. NIH Office of Dietary Supplements. Published June 17, 2011.
  5. Bowen KJ, Harris WS, Kris-Etherton PM. Omega-3 Fatty Acids and Cardiovascular Disease: Are There Benefits? Current Treatment Options in Cardiovascular Medicine. 2016;18(11). doi:10.1007/s11936-016-0487-1.
  6. Using Dietary Supplements Wisely. National Center for Complementary and Integrative Health. Published January 15, 2019.
  7. Carnett L. Influencer marketing in the ingredient and dietary supplement space. Natural Products INSIDER. Published September 24, 2018. Accessed July 18, 2019.
  8. Dietary supplement concerns? Tell the FTC and FDA. Consumer Information. Published March 13, 2018.
  9. Royne MB, Myers SD, Deitz G, Fox AK. Risks, Benefits, and Competitive Interference: Consumer Perceptions of Prescription Drug Versus Dietary Supplement Advertising. Journal of Current Issues & Research in Advertising. 2016;37(1):59-79. doi:10.1080/10641734.2015.1119769. Published January 28, 2016.
  10. Rotfeld HJ. Health Information Consumers Can’t or Don’t Want to Use. Journal of Consumer Affairs. 2009;43(2):373-377. doi:10.1111/j.1745-6606.2009.01145.x. Published June 1, 2009.
  11. Bailey RL, Gahche JJ, Miller PE. Why Adults Use Dietary Supplements. JAMA Internal Medicine. 2013;173(5):355-361. Published March 11, 2013.
  12. Age-Related Eye Disease Study Research Group. A Randomized, Placebo-Controlled, Clinical Trial of High-Dose Supplementation With Vitamins C and E, Beta Carotene, and Zinc for Age-Related Macular Degeneration and Vision Loss. Archives of Opthamology. 2001;119(10):1417-1436. doi:10.1001/archopht.119.10.1417. Published October, 2001.
  13. Supplement and Vitamin Certification - NSF International.
  14. Dietary Supplements Verification Program – US Pharmacopeia.

Inquiries regarding this publication may be directed to The information provided in this publication is intended for general consumer understanding, and is not intended to be used for medical diagnosis or treatment, or to substitute for professional medical advice.