Herbal supplements: What to know before you buy

Regulations ensure that herbal supplements meet manufacturing standards but don't guarantee that they're safe or effective. Do your homework before you buy.

By Mayo Clinic Staff

Echinacea to prevent colds. Ginkgo to improve memory. Flaxseed to lower cholesterol. The list of herbal remedies goes on and on.

Herbal supplements, sometimes called botanicals, are one type of dietary supplement available for purchase. Herbal supplements aren't new — plants have been used for medicinal purposes for thousands of years.

But herbal supplements generally haven't been subjected to the same scientific scrutiny and aren't as strictly regulated as medications. For example, although makers of herbal supplements must follow good manufacturing practices — to ensure that supplements are processed consistently and meet quality standards — they don't have to get approval from the Food and Drug Administration (FDA) before putting their products on the market.

Yet all herbs — including herbal supplement products labeled as "natural" — can have medication-like effects. Anything strong enough to produce a positive effect, such as lowered cholesterol or improved mood, is also strong enough to carry risk.

So it's important to investigate potential benefits and side effects of herbal supplements before you buy. And be sure to talk with your doctor, especially if you take medications, have chronic health problems, or are pregnant or breast-feeding.

Are herbal supplements safe?

Herbal supplements are regulated by the FDA, but not as drugs or as foods. They fall under a category called dietary supplements. The rules for dietary supplements are as follows:

  • Manufacturers don't have to seek FDA approval before selling dietary supplements.
  • Companies can claim that products address a nutrient deficiency, support health or are linked to body functions — if they have supporting research and they include a disclaimer that the FDA hasn't evaluated the claim.
  • Companies aren't allowed to make a specific medical claim. An example of a specific medical claim might be, "This herb reduces the frequency of urination due to an enlarged prostate."
  • Manufacturers must follow good manufacturing practices to ensure that supplements are processed consistently and meet quality standards. These regulations are intended to keep the wrong ingredients and contaminants out of supplements, as well as make sure that the right ingredients are included in appropriate amounts.
  • The FDA is responsible for monitoring dietary supplements that are on the market. If the FDA finds a product to be unsafe, it can take action against the manufacturer or distributor or both, and may issue a warning or require that the product be removed from the market.

These regulations provide assurance that:

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

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

These 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 prescribed medications could lead to harmful, even life-threatening results.

It's important to talk with your doctor before using herbal supplements.

How do you know what's in herbal supplements?

The FDA requires that the labels of all herbal supplements include this information:

  • The name of the herbal supplement
  • The name and address of the manufacturer or distributor
  • A complete list of ingredients — either in the Supplement Facts panel or listed beneath it
  • Serving size, amount and active ingredient

If you don't understand something on a supplement's label, ask your doctor or pharmacist for an explanation.

An easy way to compare ingredients in products is to use the Dietary Supplement Label Database, which is available on the National Institute of Health's website. The database has information on the ingredients for thousands of dietary supplements sold in the United States. You can look up products by brand name, uses, active ingredient or manufacturer.

How do you know if herbal supplements' 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 particular 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 are the National Center for Complementary and Integrative Health and the Office of Dietary Supplements. Both have websites that provide information 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 its products' claims.

Who shouldn't use herbal supplements?

If you have health issues, it's essential that you talk with your doctor before trying herbal supplements. In fact, in some high-risk situations, your doctor will likely recommend that you avoid herbal supplements altogether.

It's especially important that you talk to your doctor before using herbal supplements if:

  • You're taking prescription or over-the-counter (OTC) medications. Some herbs can cause serious side effects when mixed with prescription and OTC medications, such as aspirin, blood thinners or blood pressure medications. Talk to your doctor about possible interactions.
  • You're pregnant or breast-feeding. Medications that may be safe for you as an adult may be harmful to your fetus or your breast-feeding infant. As a general rule, don't take any medications — prescription, OTC or herbal — when you're pregnant or breast-feeding unless your doctor approves.
  • You're having surgery. Many herbal supplements can affect the success of surgery. Some may decrease the effectiveness of anesthetics or cause dangerous complications, such as bleeding or high blood pressure. Tell your doctor about any herbs you're taking or considering taking as soon as you know you need surgery.
  • You're younger than 18 or older than 65. Few herbal supplements have been tested on children or have established safe doses for children. And older adults may metabolize medications differently.

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 supplement instructions. Don't exceed recommended dosages or take the herb for longer than recommended.
  • Keep track of what you take. Take only one supplement at a time to determine if it's effective. 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 or U.S. Pharmacopeia Convention (USP).
  • Check alerts and advisories. The FDA maintains lists of supplements that are under regulatory review or that have been reported to cause adverse effects. Check the FDA website periodically for updates.
Nov. 08, 2017 See more In-depth

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