Many adults and children in the United States take one or more vitamins or other dietary supplements. In addition to vitamins, dietary supplements can contain minerals, herbs or other botanicals, amino acids, enzymes, and many other ingredients. Dietary supplements come in a variety of forms, including tablets, capsules, gummies, and powders, as well as drinks and energy bars. Popular supplements include vitamins D and B12; minerals like calcium and iron; herbs such as echinacea and garlic; and products like glucosamine, probiotics, and fish oils.
The Dietary Supplement Label
Products sold as dietary supplements come with a Supplement Facts label that lists the active ingredients, the amount per serving (dose), as well as other ingredients, such as fillers, binders, and flavorings. The manufacturer suggests the serving size, but your health care provider might decide a different amount is more appropriate for you.
Some dietary supplements can help you get adequate amounts of essential nutrients if you don’t eat a nutritious variety of foods. However, supplements can’t take the place of the variety of foods that are important to a healthy eating routine. To learn more about what makes a healthy eating routine, the Dietary Guidelines for Americans and MyPlate are good sources of information.
Some dietary supplements can improve overall health and help manage some health conditions. For example:
- Calcium and vitamin D help keep bones strong and reduce bone loss.
- Folic acid decreases the risk of certain birth defects.
- Omega-3 fatty acids from fish oils might help some people with heart disease.
- A combination of vitamins C and E, zinc, copper, lutein, and zeaxanthin (known as an AREDS formula) may slow down further vision loss in people with age-related macular degeneration (AMD).
Many other supplements need more study to determine if they have value. The U.S. Food and Drug Administration (FDA) does not determine whether dietary supplements are effective before they are marketed.
Safety and Risk
Many supplements contain active ingredients that can have strong effects in the body. Always be alert to the possibility of a bad reaction, especially when taking a new product.
You are most likely to have side effects from dietary supplements if you take them at high doses or instead of prescribed medicines, or if you take many different supplements. Some supplements can increase the risk of bleeding or, if taken before surgery, can change your response to anesthesia. Supplements can also interact with some medicines in ways that might cause problems. Here are a few examples:
- Vitamin K can reduce the ability of the blood thinner warfarin to prevent blood from clotting.
- St. John’s wort can speed the breakdown of many medicines and reduce their effectiveness (including some antidepressants, birth control pills, heart medications, anti-HIV medications, and transplant drugs).
- Antioxidant supplements, such as vitamins C and E, might reduce the effectiveness of some types of cancer chemotherapy.
Manufacturers may add vitamins, minerals, and other supplement ingredients to foods you eat, especially breakfast cereals and beverages. As a result, you may get more of these ingredients than you think, and more might not be better. Taking more than you need costs more and might also raise your risk of side effects. For example, too much vitamin A can cause headaches and liver damage, reduce bone strength, and cause birth defects. Excess iron causes nausea and vomiting and may damage the liver and other organs.
Be cautious about taking dietary supplements, beyond a standard prenatal supplement, if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their health care provider. Many supplements have not been well tested for safety in children and in those who are pregnant or nursing.
If you think that you have had a bad reaction to a dietary supplement, let your health care provider know. They may report your experience to the FDA. You may also submit a report directly to the FDA by calling 800-FDA-1088 or completing an online form. You should also report your reaction to the manufacturer by using the contact information on the product label.
The FDA has established good manufacturing practices (GMPs) that companies must follow to help ensure the identity, purity, strength, and composition of their dietary supplements. These GMPs can prevent adding the wrong ingredient (or too much or too little of the correct ingredient) and reduce the chance of contamination or improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture supplements.
Several independent organizations offer quality testing and allow products that pass these tests to display a seal of quality assurance that indicates the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. These seals do not guarantee that a product is safe or effective. Organizations that offer quality testing include:*
- NSF International
- U.S. Pharmacopeia
* Any mention of a specific company, organization, or service does not represent an endorsement by ODS.
Talk with Your Health Care Providers
Tell your health care providers (including doctors, dentists, pharmacists, and dietitians) about any dietary supplements you’re taking. They can help you determine which supplements, if any, might be valuable for you.
Keep a complete record of any dietary supplements and medicines you take. The Office of Dietary Supplements website has a useful form, ”My Dietary Supplement and Medicine Record,” that you can print and fill out at home. For each product, note the name, the dose you take, how often you take it, and the reason for use. You can share this record with your health care providers to discuss what’s best for your overall health.
Keep in Mind
- Consult your health care provider before taking dietary supplements to treat a health condition.
- Get your health care provider’s approval before taking dietary supplements in place of, or in combination with, prescribed medicines.
- If you are scheduled to have any type of surgical procedure, talk with your health care provider about any supplements you take.
- Keep in mind the term “natural” doesn’t always mean safe. Some all-natural botanical products, for example, like comfrey and kava, can harm the liver. A dietary supplement’s safety depends on many things, such as its chemical makeup, how it works in the body, how it is prepared, and the amount you take.
- Before taking any dietary supplement, use the information sources listed in this brochure and talk to your health care providers to answer these questions:
- What are its potential benefits for me?
- Does it have any safety risks?
- What is the proper dose to take?
- How, when, and for how long should I take it?
Federal Regulation of Dietary Supplements
Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. The FDA is the federal agency that oversees both supplements and medicines, but the FDA regulations for dietary supplements are different from those for prescription or over-the-counter medicines.
Medicines must be approved by the FDA before they can be sold or marketed. Supplements do not require this approval. Supplement companies are responsible for having evidence that their products are safe, and the label claims are truthful and not misleading. However, as long as the product does not contain a “new dietary ingredient” (one introduced since October 15, 1994), the company does not have to provide this safety evidence to the FDA before the product is marketed.
Dietary supplement labels may include certain types of health-related claims. Manufacturers are permitted to say, for example, that a supplement promotes health or supports a body part or function (like heart health or the immune system). These claims must be followed by the words, “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.”
Manufacturers must follow good manufacturing practices (GMPs) to ensure the identity, purity, strength, and composition of their products. If the FDA finds a dietary supplement to be unsafe, it may remove the product from the marketplace or ask the manufacturer to voluntarily recall the product.
The FDA monitors the marketplace for potential illegal products that may be unsafe or make false or misleading claims. The Federal Trade Commission, which monitors product advertising, also requires information about a supplement product to be truthful and not misleading.
The federal government can take legal action against companies and websites that sell dietary supplements when the companies make false or deceptive statements about their products, if they promote them as treatments or cures for diseases, or if their products are unsafe.
Federal Government Information Sources on Dietary Supplements
NATIONAL INSTITUTES OF HEALTH (NIH)
NIH supports research and provides educational materials on dietary supplements.
- Office of Dietary Supplements (ODS)
ODS provides accurate and up-to-date scientific information about dietary supplements.
- National Center for Complementary and Integrative Health (NCCIH)
NCCIH also has scientific information about dietary supplement ingredients.
- National Library of Medicine
Medline Plus provides trusted health information.
PubMed contains more than 35 million citations from the scientific literature.
- NIH Health Information
Information about healthy living and wellness from across NIH.
U.S. FOOD AND DRUG ADMINISTRATION (FDA)
FDA issues rules and regulations and oversees dietary supplement labeling, marketing, and safety. Recall notices are also posted on the FDA webpage or you can subscribe to receive FDA notices of recalls, market withdrawals, and safety alerts.
FEDERAL TRADE COMMISSION (FTC)
U.S. DEPARTMENT OF AGRICULTURE (USDA)
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES (HHS)
This fact sheet by the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.