Herbal supplements: What to know before you buy

Regulations ensure that herbal supplements meet manufacturing standards but aren't a guarantee of effectiveness. Do your homework before you buy.

By Mayo Clinic Staff

Echinacea to prevent colds. Ginkgo to improve memory. Herbal remedies aren't new — plants have been used for medicinal purposes for thousands of years.

But herbal supplements generally haven't received the same scientific scrutiny and aren't as strictly regulated as medications. Yet herbs and herbal products — including those labeled as "natural" — can have strong effects in the body.

It's important to learn about potential benefits and side effects of herbal supplements before you buy. Be sure to talk with your doctor, especially if you take any medicines, have a chronic health problem, or are pregnant or breastfeeding.

Are herbal supplements regulated?

Herbal supplements are regulated by the U.S. Food and Drug Administration (FDA), but not as strictly as prescription or over-the-counter (OTC) drugs. They fall under a category called dietary supplements.

Dietary supplement makers don't need FDA approval to sell their products, but they must:

  • Ensure that their supplements are free of contaminants and that they're accurately labeled.
  • Have research to support claims that a product addresses a nutrient deficiency or supports health, and include a disclaimer that the FDA hasn't evaluated the claim.
  • Avoid making specific medical claims. For example, a company can't say: "This herb reduces the frequency of urination due to an enlarged prostate." The FDA can take action against companies that make false or unsupported claims to sell their supplements.

These regulations provide assurance that:

  • Herbal supplements meet certain quality standards
  • The FDA can remove dangerous products from the market

However, the rules don't guarantee that herbal supplements are safe for anyone to use.

Who shouldn't use herbal supplements?

Herbal products can pose unexpected risks because many supplements contain active ingredients that have strong effects in the body. For example, taking a combination of herbal supplements or using supplements together with prescription drugs could lead to harmful, even life-threatening results.

It's especially important to talk with your doctor about herbal supplements if:

  • You're taking prescription or OTC medications. Some herbs can cause serious side effects when mixed with medications such as aspirin, blood thinners and blood pressure medications.
  • You're pregnant or breastfeeding. Medications that may be safe for you as an adult may be harmful to your baby.
  • You're having surgery. Many herbal supplements can affect the success of surgery. Some may decrease the effectiveness of anesthesia or cause dangerous complications, such as bleeding.
  • You're younger than 18 or older than 65. Few herbal supplements have been tested in children or have established safe doses for children. And older adults may metabolize medications differently.

How do you know what's in herbal supplements?

The FDA requires that supplement labels include this information:

  • Name of the supplement
  • Name and address of the manufacturer or distributor
  • Complete list of ingredients
  • Serving size, amount and active ingredient

If you don't understand something on the label, ask your doctor or pharmacist to explain.

An easy way to compare ingredients in products is to use the Dietary Supplement Label Database, which is available on the website for the U.S. National Institute of Health. You can look up products by brand name, use, active ingredient or manufacturer.

How do you know if supplement claims are true?

Manufacturers of herbal supplements are responsible for ensuring that the claims they make about their products aren't false or misleading and that they're backed up by adequate evidence. But they aren't required to submit this evidence to the FDA.

So be a smart consumer. Don't just rely on a product's marketing. Look for objective, research-based information to evaluate a product's claims.

To get reliable information about a supplement:

  • Ask your doctor or pharmacist. Even if they don't know about a specific supplement, they may be able to point you to the latest medical guidance about its uses and risks.
  • Look for scientific research findings. Two good sources in the U.S. are the National Center for Complementary and Integrative Health, and the Office of Dietary Supplements. Both have websites to help consumers make informed choices about dietary supplements.
  • Contact the manufacturer. If you have questions about a specific product, call the manufacturer or distributor. Ask to talk with someone who can answer questions, such as what data the company has to substantiate product claims.

Safety tips for using herbal supplements

If you've done your homework and plan to try an herbal supplement, play it safe with these tips:

  • Follow instructions. Don't exceed recommended dosages or take for longer than recommended.
  • Keep track of what you take. Make a note of what you take — and how much for how long — and how it affects you. Stop taking the supplement if it isn't effective or doesn't meet your goals for taking it.
  • Choose your brand wisely. Stick to brands that have been tested by independent sources, such as ConsumerLab.com, U.S. Pharmacopeia and NSF International.
  • Check alerts and advisories. The FDA maintains a list of supplements that are under regulatory review or that have been reported to cause adverse effects. Check the FDA website periodically for updates.

Get the latest health advice from Mayo Clinic delivered to your inbox.

Sign up for free, and stay up-to-date on research advancements, health tips and current health topics, like COVID-19, plus expert advice on managing your health.

To provide you with the most relevant and helpful information and to understand which information is beneficial, we may combine your e-mail and website usage information with other information we have about you. If you are a Mayo Clinic Patient, this could include Protected Health Information (PHI). If we combine this information with your PHI, we will treat all of that information as PHI, and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of e-mail communications at any time by clicking on the Unsubscribe link in the e-mail.

Jan. 09, 2021 See more In-depth

See also

  1. Add flax to your baking
  2. Calcium
  3. Calcium for better bones
  4. Calcium supplements for men
  5. Timing calcium supplements
  6. Calcium: Think outside the carton
  7. COVID-19 and vitamin D
  8. Can vitamins help prevent a heart attack?
  9. Can zinc supplements help treat hidradenitis suppurativa?
  10. Vitamin C and mood
  11. Eye vitamins: Can they prevent or treat glaucoma?
  12. Fiber supplements
  13. Flaxseed best when ground
  14. Flaxseed for breakfast?
  15. Ground flaxseed
  16. Heartburn medicines and B-12 deficiency
  17. I have heavy periods. Should I take an iron pill?
  18. Integrative medicine: Different techniques, one goal
  19. Kratom and pregnancy: Not a safe mix
  20. Multivitamins for kids
  21. Nutrition: Does it come in a pill?
  22. Percent Daily Value
  23. Prebiotics, probiotics and your health
  24. Prenatal vitamins
  25. Magnesium supplements
  26. Nutritional supplements
  27. Are dietary supplements right for you?
  28. Bromelain
  29. Calories and nutrients to fuel sports performance
  30. Curcumin
  31. Dietary supplements: What to know before you buy
  32. Is your dietary supplement safe?
  33. Melatonin
  34. Smart practices for healthy living
  35. Tips for staying supplement savvy
  36. What are omega-3 fatty acids from fish oil?
  37. What are probiotics?
  38. What are multivitamin/mineral dietary supplements?
  39. What is Boswellia?
  40. What is ginger?
  41. What is whey protein?
  42. Vitamin C megadoses
  43. Vitamin C: An essential nutrient
  44. Vitamin D and MS: Any connection?
  45. Vitamin D: Can it prevent Alzheimer's & dementia?
  46. Vitamin D deficiency
  47. Can having vitamin D deficiency cause high blood pressure?
  48. Vitamin D: Essential with calcium
  49. Vitamin D for babies
  50. Vitamin D toxicity
  51. Vitamins for MS: Do supplements make a difference?
  52. What does a 'seal of approval' mean?
  53. Wheatgrass