A few dietary supplements are clearly beneficial to health. For example:

• Folic acid can help pregnant women reduce the risk of having a child with birth defects;
• A mix of nutrients (vitamins C and E, zinc, copper, and lutein) can slow vision loss in people with macular degeneration; 
• Calcium and iron can help people who don’t get enough of those nutrients from food;
• Vitamin D can help people who don't get enough sunlight living in northern latitudes during the winter or those with vitamin D deficiency;
• Vitamin B-12 can help older people who cannot digest and absorb the B-12 in foods very well.

But these and other medically supported uses of supplements are the exceptions. When it comes to the dietary supplement marketplace, misinformation, exaggeration, deception, and even scams abound.  Our Consumer’s Guide, below, can help you identify dubious claims, understand the potential health risks in taking supplements, and use resources with credible and accurate information. On this page, you will find information on:

• The risks associated with dietary supplements,
• Claims and business practices that can mislead you,
• CSPI dietary supplement resources and advocacy,
• Nutrition Action Healthletter articles, 
• Additional Public Resources, and
• Reporting supplement problems to FDA.

Please remember, taking dietary supplements can impact your health and other medical treatments. The information on this page is for informational purposes only. Each dietary supplement can impact each person differently, and you should always consult a medical professional before taking a dietary supplement.

Be aware of the risks of taking supplements.

The federal law that governs oversight of supplements is riddled with loopholes, and important rules are rarely enforced. Many consumers assume that, like prescription drugs, all supplements must be proven safe and effective before being sold to the public. Unfortunately, this is generally not the case.

Investigations by the Center for Science in the Public Interest find that claims that dietary supplement manufacturers make about the benefits of their products are frequently misleading or unsubstantiated. In addition:

• Hundreds of weight-loss, workout, and sexual enhancement supplements also have been found by federal regulators to be tainted with unlabeled stimulants or illegal, dangerous drugs;
• Supplements can have potentially harmful interactions with certain prescription drugs or medical conditions.
• Other supplements may contain allergens that are not declared on the labels;
• And some supplements, especially herbal products, do not contain exactly what’s on the label. The adulteration of herbal supplements with fillers and synthetic chemicals intended to fool quality-control testing is rampant worldwide and has persisted as a problem for years. 

For example, St. John’s Wort, a supplement that is believed by some to treat depression, menopausal symptoms, and smoking addiction (among other ailments) interacts with critical prescription medications, including blood thinners, anti-retroviral medications for HIV/AIDS, antidepressants, birth-control pills, some cancer medications, and other necessary medications. In addition, the drug is prone to other side effects such as increased sensitivity to sunlight, anxiety, dizziness, gastrointestinal symptoms, and sexual dysfunction.

Other supplements, including those that are commonly consumed, have also been associated with a range of serious and problematic health conditions, such as gingko biloba and saw palmetto.

Beware of claims and business practices intended to mislead you.

According to the Federal Trade Commission (FTC), here are some examples of common claims and business practices in the dietary supplement market that you should watch out for:

• “Natural” or “non-toxic:” Such claims do not mean that a supplement has no side effects or is safe to use. 
• “Treat,” “prevent,” or “cure” claims: Avoid any supplement that claims to treat, prevent, or cure diseases like cancer, dementia, depression, and diabetes, or conditions like ADHD or drug addiction. Claims like these are unproven, illegal and make a supplement an unapproved drug by law.
• “Supports,” “maintains,” or “enhances” claims: Supplements can make these kids of fuzzy claims with very little evidence. Be skeptical..
• Testimonials: Unfortunately, fake online reviews of products are now common.  
• Claims suggesting proven effectiveness without citing a credible source: These include phrases like “scientific breakthrough,” “clinically proven,” “miraculous cure,” “secret ingredient,” or “ancient remedy.” Ignore them. Be aware that some labels or websites cite poor-quality studies that were funded or conducted by the company.
• “Cure-all” claims for a wide variety of ailments: If something sounds too good to be true, it usually is.
• “Patented:” Patents are awarded to ideas that are novel, non-obvious, and potentially useful, but that is no guarantee that they actually work.
• “Free trial:”. This most likely means free only if you can quickly cancel the sale, sometimes before you have time to evaluate the product. Otherwise, the supplement manufacturer may start charging your credit card hefty monthly fees.
• “Money-back” guarantee: The fine print in the “guarantee” may make it impossible to get your money back.
• Risky websites: Avoid websites that fail to list the company’s name, street address, phone number, or other contact information. They often have something to hide and you’ll have no way to contact them if your purchase never arrives.

Additional CSPI resources and advocacy on dietary supplements​

• Smoking cessation supplements:
  • FDA Urged to Take Enforcement Action against Manufacturers of Dietary Supplements that Promise to Help Smokers Quit
• Anti-opioid supplements:
  • Say it Ain’t So: Supplement Companies Actually Claim Their Vitamins, Minerals, and Herbs Can Help Reduce Opioid-withdrawal Symptoms
  • FDA, FTC Warn Companies Marketing Supplements as Opioid Addiction Withdrawal Aids
• Fertility supplements:
  • Manufacturers of “Fertility” Supplements Selling False Hope
  • Appendix to Letters to FDA and FTC re: Fertility Supplements: contains information regarding specific supplements and their claims
• COVID-19 and immunity supplements:
  • Walking the Immunity Tightrope
  • CSPI Urges FDA Enforcement Action on Televangelist Jim Bakker’s Fake Coronavirus “Cure”
  • “Immune Boosterism” from Dr. Peter Lurie’s blog, Beyond the Curve
  • CSPI Urges Federal Enforcement Action Against Supplement Manufacturers Making Illegal Antiviral Claims
• Pure, powdered caffeine:
  • FDA Finally Takes Enforcement Action against Distributors of Deadly Powdered Caffeine
  • Additional CSPI Articles on Caffeine
•  Cannabis (including CBD):
  • Letter to Congress on CBD Safety and Regulation
  • FDA Says Cannabidiol is not Generally Recognized as Safe, and Warns More Sellers
  • CSPI Urges FDA to Take Steps to Reduce Risks of Cannabis Use
  • Additional CSPI Articles on Cannabis
• Other resources:
  • Additional CSPI Articles on Supplements

Nutrition Action Healthletter articles on dietary supplements

CSPI’s Nutrition Action Healthletter also offers clear, research-based information on supplements.  Below is a selection of past coverage of the issue from Nutrition Action.  

• Multiple Choice: How to Find the Best Multivitamin (March 2020)
• Bone Smarts: Calcium and Vitamin D (July/August 2017)
• Foods & Immunity: What’s the Catch? (June 2020)
• Can Supplements Boost Your Immune System? (March 2020)
• How Some Supplements Interfere with Medications (March 2019)
• Tainted Supplements: Are You Taking Hidden Drugs? (January/February 2019)
• Bugs with Benefits? Probiotics May Not Be Harmless (December 2018)
• Ginkgo No-go: Filler, Anyone? (May 2018)
• Probiotics: What’s in a Name? (July/August 2017)
• Scam Watch: How to Succeed in the Supplement Business Without Really Trying (March 2016)
• Clicker Beware: a guide on how to avoid supplement scams online (March 2015)

To get up-to-date information on supplements and for more articles on nutrition, subscribe to Nutrition Action today.

Additional Public Resources

Unsure about certain supplements? Try these additional public resources:

• Your healthcare provider: Your primary care physician, physician’s assistant, nurse practitioner, or pharmacist may be able to discuss your health needs and the benefits and risks of taking supplements. They may also be able to make sure that a dietary supplement doesn’t interact with your medications.
• National Institutes of Health (NIH): Free fact sheets, prepared by expert scientists, cover many of the most popular dietary supplements and include information about the proven benefits, if any, the proper dosages, and potential adverse effects from using the supplements.
• FDA Consumer Updates: A few times a year, FDA publishes a “Consumer Update” cautioning consumers about an unsafe or fraudulent category of supplements.

Reporting supplement issues to the FDA

If you or someone you know may have suffered a bad reaction or adverse event from taking a dietary supplement:

Tell the Food and Drug Administration. The FDA’s Adverse Event Reporting System (CAERS) allows consumers, health professionals, manufacturers, researchers, and public health officials to report safety concerns about dietary supplements. You can file a report on FDA’s Safety Reporting Portal (SRP) https://www.accessdata.fda.gov/scripts/medwatch/.