Frequently Asked Questions (FAQ)

Table of Contents

Use and Safety of Dietary Supplements

How do I know if I need a dietary supplement?

How can I get more information about a particular dietary supplement such as whether it is safe and effective?

Where can I find information about the use of dietary supplements for a particular health condition or disease?

What is the difference between the RDA and DV for a vitamin or mineral?

Where can I report a complaint about a particular dietary supplement or find contact information for a supplement company?

Purchasing Dietary Supplements

Where can I purchase dietary supplements?

Which brand(s) of dietary supplements should I purchase?

How do I know if the supplement that I purchased contains the ingredients that it claims on the label or if it is contaminated?

With so many dietary supplements to choose from, how can I compare the ingredients and doses in one product with those in another?

Regulatory Information

Who is responsible for overseeing the regulation of dietary supplements in the United States?

How do I produce, market, import, distribute or sell a dietary supplement in the United States?

Dietary Supplement Sales and Market Data

Where can I locate information or data on dietary supplement sales and usage?

ODS Web site Materials and Link Requests

Can I reproduce fact sheets and other materials found on the Office of Dietary Supplements Web site?

Can I add a link to the Office of Dietary Supplements Web site from my Web site?

How can I nominate my Web site for a link from the Office of Dietary Supplements Web site?

Media Inquiries

I am with the media and would like to talk with someone from the Office of Dietary Supplements about my dietary supplement questions. How should I proceed?

Use and Safety of Dietary Supplements

Q. How do I know if I need a dietary supplement?

A. Because many products are marketed as dietary supplements, it is important to remember that supplements include vitamins and minerals, as well as herbs, botanicals and other substances.

Some supplements may help ensure that you get adequate amounts of essential nutrients or help promote optimal health and performance if you do not consume a variety of foods, as recommended in the MyPlateexternal link icon and Dietary Guidelines for Americansexternal link icon.

However, dietary supplements are not intended to treat, diagnose, mitigate, prevent, or cure disease. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery or with other dietary supplements or medicines, or if you have certain health conditions.

Do not self diagnose any health condition. Work with your health care provider to determine how best to achieve optimal health and always check with your health care provider before taking a supplement, especially when combining or substituting them with other foods or medicine.

Q. How can I get more information about a particular dietary supplement such as whether it is safe and effective?

A. Scientific evidence supporting the benefits of some dietary supplements (e.g., vitamins and minerals) is well established for certain health conditions, but others need further study. This is partly due to the way dietary supplements are regulated by the U.S. Food and Drug Administration (FDA).

Research studies in people to prove that a dietary supplement is safe are not required before the supplement is marketed, unlike for drugs. It is the responsibility of dietary supplement manufacturers/distributors to ensure that their products are safe and that their label claims are accurate and truthful. If the FDA finds a supplement to be unsafe once it is on the market, only then can it take action against the manufacturer and/or distributor, such as by issuing a warning or requiring the product to be removed from the marketplace.

The manufacturer does not have to prove that the supplement is effective, unlike for drugs. The manufacturer can say that the product addresses a nutrient deficiency, supports health, or reduces the risk of developing a health problem, if that is true. If the manufacturer does make a claim, it must be followed by the statement "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

Dietary supplements are not intended to treat, diagnose, mitigate, prevent, or cure disease. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery or with other dietary supplements or medicines, or if you have certain health conditions. Whatever your choice, supplements should not replace prescribed medications or the variety of foods important to a healthful diet.

Do not self diagnose any health condition. Work with your health care provider to determine how best to achieve optimal health and always check with your health care provider before taking a supplement, especially when combining or substituting them with other foods or medicine.

In addition to talking with your health care provider about dietary supplements, you can search on-line for information about a particular dietary supplement. It is important to ensure that you obtain information from reliable sources such as:

Fact sheets on dietary supplements from the National Institutes of Health

Nutrient Recommendations: Dietary Reference Intakes (DRI) and Recommended Dietary Allowances (RDA)

PubMed Dietary Supplement Subset

Dietary supplement warnings and safety information from the U.S. Food and Drug Administrationexternal link icon

Consumer information from the Federal Trade Commissionexternal link icon

For tips on evaluating sources of healthcare information on the Internet, please see the following document: How to Evaluate Health Information on the Internet: Questions and Answers.

Q. Where can I find information about the use of dietary supplements for a particular health condition or disease?

A. Scientific evidence supporting the benefits of some dietary supplements (e.g., vitamins and minerals) is well established for certain health conditions, but others need further study. Whatever your choice, supplements should not replace prescribed medications or the variety of foods important to a healthful diet.

Dietary supplements are not intended to treat, diagnose, mitigate, prevent, or cure disease. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery or with other dietary supplements or medicines, or if you have certain health conditions.

Do not self diagnose any health condition. Work with your health care provider to determine how best to achieve optimal health and always check with your health care provider before taking a supplement, especially when combining or substituting them with other foods or medicine.

In addition to talking with your health care provider about dietary supplements for a particular health condition or disease, you can search on-line for information. It is important to ensure that you obtain information from reliable sources such as:

Health Information from the National Library of Medicine's MedlinePlus Database

Fact sheets on dietary supplements from the National Institutes of Health

PubMed Dietary Supplement Subset

For tips on evaluating sources of healthcare information on the Internet, please see the following document: How to Evaluate Health Information on the Internet: Questions and Answers.

Q. What is the difference between the RDA and DV for a vitamin or mineral?

Many terms are used when referring to either the amount of a particular nutrient (such as calcium or vitamin D) you should get or the amount in a food or dietary supplement. The two most common are the Recommended Dietary Allowance (RDA) and the Daily Value (DV). These terms can be confusing

RDAs are recommended daily intakes of a nutrient for healthy people. They tell you how much of that nutrient you should get on average each day. RDAs are developed by the Food and Nutrition Board at the Institute of Medicine of the National Academies. They vary by age, gender and whether a woman is pregnant or breastfeeding; so there are many different RDAs for each nutrient.

DVs, established by the U.S. Food and Drug Administration (FDA), are used on food and dietary supplement labels. For each nutrient, there is one DV for all people ages 4 years and older. Therefore, DVs aren't recommended intakes, but suggest how much of a nutrient a serving of the food or supplement provides in the context of a total daily diet. DVs often match or exceed the RDAs for most people, but not in all cases.

DVs are presented on food and supplement labels as a percentage. They help you compare one product with another. As an example, the %DV for calcium on a food label might say 20%. This means it has 200 mg (milligrams) of calcium in one serving because the DV for calcium is 1,000 mg/day. If another food has 40% of the DV for calcium, it's easy to see that it provides much more calcium than the first food.

The FDA has a Web page that lists the DVs for all nutrients and provides additional details.

Q. Where can I report a complaint about a particular dietary supplement or find contact information for a supplement company?

A. To report an illness or injury associated with a dietary supplement, please talk with your health care provider and contact the U.S. Food and Drug Administration (FDA).

To report a complaint involving misleading advertising, fraud, or other consumer protection matters associated with a dietary supplement, please contact the Federal Trade Commission (FTC). The FTC also has a helpful web page with tips for resolving common consumer problems that provides links to state, local and national organizations that might be able to help.

If you are having trouble finding contact information for a dietary supplement manufacturer or distributor, check our Dietary Supplement Label Database. It provides contact information for many dietary supplement companies.