Many products are marketed as dietary supplements, and it is important to remember that supplements include not only vitamins and minerals, but also herbs and other botanicals, probiotics, fish oil, 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 regularly consume a wide variety of foods.

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. Also check with your health care provider before taking a supplement, especially if you take any medicines or other dietary supplements or if you have any health conditions.

To get a list of all vitamins and minerals and how much you need, check out this quick anonymous free online tool from the U.S. Department of Agriculture.

Keep in mind that the amounts of vitamins and minerals you need include everything you get from food and beverages—you may or may not need a dietary supplement to achieve these amounts. Talk with your health care provider to help you determine which supplements, if any, might be valuable for you.

For more detailed information about each vitamin and mineral, read our vitamin and mineral fact sheets.

Scientific evidence supporting the benefits of some dietary supplements (for example, 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 healthy 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. Also, check with your health care provider before taking a supplement, especially if you take any medicines or other dietary supplements or if you have any health conditions.

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
• ODS dietary supplement fact sheets

 All products labeled as dietary supplements carry a Supplement Facts label that is similar to the Nutrition Facts label found on food products. It lists the active ingredients and their amounts, plus other added ingredients like fillers, binders, and flavorings. It also gives a suggested serving size, but you and your health care provider might decide that a different amount is more appropriate for you.

In the Supplement Facts label, the amounts of vitamins, minerals, and other nutrients like dietary fiber are listed as a percentage of the Daily Value (%DV). Each nutrient has one DV that applies to all people aged 4 and older. For example, the DV for vitamin C is 90 milligrams (mg) and the DV for the B-vitamin biotin is 30 micrograms (mcg).

The %DV allows you to see how much a product contributes to your approximate daily needs for that nutrient. For example, if a supplement provides 50% of the DV for calcium, it contributes about half of your daily needs for calcium.

The U.S. Food and Drug Administration (FDA) has a webpage that describes the Nutrition Facts label and DV in more detail.

Good places to start are the ODS dietary supplement fact sheets, which provide helpful information about dietary supplement ingredients including recommended amounts, health effects, safety, and medication interactions.

Many of the ODS fact sheets come in three versions—the easy-to-read Consumer version in both English and Spanish, and the more detailed Health Professional version. Read them online or print a copy.

In addition, Herbs at a Glance fact sheets from the National Center for Complementary and Integrative Health (NCCIH) provide basic information on specific herbs and botanicals—common names, uses, potential side effects, and resources for more information.

You can search for medical and scientific studies on specific dietary supplement ingredients using PubMed. PubMed is a database of the National Library of Medicine that provides access to over 35 million journal citations for biomedical literature from MEDLINE, life science journals, and online books.