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Dietary supplements may seem like harmless health boosters. But while some have proven benefits, many don't. Unlike drugs, dietary supplements aren't evaluated or reviewed by FDA for safety and effectiveness, and even "natural" supplements can be risky depending on the medicines you take or the medical conditions you have. In recent years, hundreds of supplements also have been found to be tainted with drugs and other chemicals. Always talk to your doctor before you take a new supplement, and avoid any supplement claiming it's a "cure."

Produced in cooperation with the Food and Drug Administration

What's a Dietary Supplement?

Dietary supplements include:

Dietary Supplement Ads Infographic: While some dietary supplements have proven benefits, others don’t. And some could even be risky for your health.

Dietary Supplement Ads

  • vitamins and minerals
  • amino acids
  • enzymes
  • herbs
  • animal extracts
  • probiotics

They come in a number of forms, including capsules, liquids, and powders. But while dietary supplements might seem similar to drugs, and some even have drug-like effects, there's a big difference: Dietary supplements don't undergo FDA review for safety and effectiveness before they're sold.

Are Dietary Supplements Safe?

Dietary supplements aren't always safe or harmless. Even "natural" supplements can be risky for people on certain medicines or with certain medical conditions, and some supplements have been found to be tainted with drugs or other chemicals. See Tainted Products.

Even "traditional remedies" with a long history of use aren't guaranteed to be safe in all cases.

Substances for which safety concerns have been raised include:

  • comfrey
  • chaparral
  • lobelia
  • germander
  • aristolochia
  • ephedra (ma huang)
  • L-tryptophan
  • germanium
  • magnolia-stephania
  • stimulant laxative ingredients, like those found in dieter's teas

Comfrey, for example, contains certain alkaloids that can cause serious liver damage, and aristolochia can cause kidney failure.

Even some vitamins and minerals, when taken in inappropriate amounts, can cause problems. For example, too much vitamin A can reduce bone mineral density, cause birth defects, and lead to liver damage, according to the National Academy of Sciences.

Always read labels and package inserts and follow product directions. But remember that dietary supplement labels and ingredients aren't evaluated by FDA before they're sold. Check with your health care professional — your best and most important source on whether a supplement is safe for you.

For a list of the dietary supplement ingredients for which FDA has issued alerts, visit FDA's website.

Supplements Claiming to be Cures

Promises for a quick cure or solution for a serious health problem may be hard to resist — but supplements claiming to shrink tumors, cure insomnia, cure impotency, treat Alzheimer's disease, or prevent severe memory loss aren't proven. Besides cheating you out of your money, they also may hurt your health.

Under Federal law, dietary supplements can't be promoted for the treatment of a disease because they aren't proven to be safe and effective.

Treat weight loss products with suspicion, too. Claims that you can eat all you want and still lose weight effortlessly just aren't true. To lose weight — and keep it off — you have to eat fewer calories and increase your activity.

Other tip-offs to a fraud include:

Claims that one product does it all and cures a wide variety of health problems.

"Proven to treat rheumatism, arthritis, infections, prostate problems, ulcers, cancer, heart trouble, hardening of the arteries and more."

Suggestions the product can treat or cure diseases.

"Shrinks tumors," "Cures impotency," or "Prevents severe memory loss."

Words like scientific breakthrough, miraculous cure, exclusive product, secret ingredient, or ancient remedy.

"A revolutionary innovation formulated by using proven principles of natural health-based medical science."

Misleading use of scientific-sounding terms.

"Molecule multiplicity," "glucose metabolism," "thermogenesis," or "insulin receptor sites."

Phony references to Nobel Prize winning technology or science.

"Nobel Prize Winning Technology," or "Developed by two times Nobel prize winner."

Undocumented testimonials by patients or doctors claiming miraculous results.

"My husband has Alzheimer's disease. He began eating a teaspoonful of this product each day. And now, in just 22 days, he mowed the grass, cleaned out the garage, weeded the flower beds, and we take our morning walk again."

Limited availability and a need to pay in advance.

"Hurry. This offer will not last. Send us a check now to reserve your supply."

Promises of no-risk "money-back guarantees.

"If after 30 days you have not lost at least 4 pounds each week, your uncashed check will be returned to you."

FDA's Rules for Health Claims

What kinds of claims can companies make on food and supplement labels? FDA-approved claims:

  • Must be based on significant scientific evidence that shows a strong link between a food substance and a disease or health condition.
  • Can state only that a food substance reduces the risk of certain health problems — not that it can treat or cure a disease. For example: "Calcium may reduce the risk of the bone disease osteoporosis. "

Dietary supplements also can carry claims about the effect of a substance on maintaining the body's normal structure or function — "Product B promotes healthy joints and bones" — but must include the disclaimer: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent disease."

Learn more at FDA's website.

Tainted Products

In the last few years, FDA has discovered hundreds of "dietary supplements" containing drugs or other chemicals, particularly in products for weight loss, sexual enhancement, or bodybuilding.

The "extra ingredients" generally aren't listed on the label, but could cause serious side effects or interact in dangerous ways with medicines or other supplements you're taking. People have suffered strokes, acute liver injury, kidney failure, and pulmonary embolisms (artery blockage in the lung); some people have died.

Tainted supplements often are sold with false and misleading claims like "100% natural" and "safe." To recognize tainted products, look for:

  • products claiming to be alternatives to FDA-approved drugs or have effects similar to prescription drugs
  • products claiming to be legal alternatives to anabolic steroids
  • marketing materials primarily in a foreign language
  • promises of rapid effects or results

Find more on tainted products marketed as dietary supplements at FDA's website.

Other Resources

Health Fraud
FDA resources to help you avoid health fraud.

Dietary Supplements
An overview of dietary supplements and other consumer information from FDA.

Buying Medicines and Medical Products Online
Tips and precautions for buying medical products online from FDA.

Office of Dietary Supplements
Information from the National Institutes of Health about dietary supplements.

How to Report a Potential Problem

To report a health product you believe is advertised falsely, contact the FTC. You also can contact your state Attorney General's office, your state department of health, or your local consumer protection agency.

To report a fraudulently labeled product, call your local FDA office.

To report an adverse reaction or illness that may be related to the use of a supplement or other health care product, call a doctor or other health care provider immediately. You also may want to report your reaction or illness to FDA MedWatch. Call 1-800-FDA-1088 (1-800-332-1088) to request a report form, or file a complaint online. Patients' names are kept confidential.

Food and Drug Administration (FDA)

FDA regulates over $1 trillion worth of products, which account for 25 cents of every dollar spent annually by American consumers. It is part of FDA's job to see that the food we eat is safe and wholesome, and that the medicines and medical devices we use are safe and effective. For more information, call toll-free, 1-888-INFO-FDA (1-888-463-6332), or visit