3 supplements you should never take

Vitamin and mineral pills rarely improve health—and some pose risks. These ingredients have been linked to so many or such severe dangers that you should never take them for any reason.

Yohimbe

Its prescription form (yohimbine hydrochloride) is used under close medical supervision to treat erectile dysfunction. But it's risky to use the versions found over-the-counter, because the ingredient can cause high or low blood pressure, rapid heart rate, and other problems.

Kava

Taken to relieve stress and anxiety, it has been linked to liver damage, including cirrhosis and hepatitis.

Aconite

Used to relieve inflammation and joint pain, it can cause nausea, vomiting, low blood pressure, respiratory-system paralysis, heart-rhythm disorders, and even death.

5 tips for using supplements safely

With lax regulation and little oversight from the Food and Drug Administration, consumers need to be especially vigilant about safety when it comes to dietary supplements. Here are five steps recommended by our medical advisers and safety experts:

1. Rather than pills, focus on getting your nutrients through a balanced diet that includes plenty of plant foods, which have been shown to provide a wide range of health benefits that supplements haven't been able to match.

2. Talk with your doctor about any supplements you might be considering—because you're concerned about a specific nutrient deficiency, say—and ask whether he or she agrees.

3. Tell your health providers about any supplements you already take, because they can interact with medication. For example, St. John's wort and vitamin D might decrease the effectiveness of many drugs, including birth control pills, heart medications, and drugs for HIV/AIDS.

4. If your doctor does recommend a supplement, look for products that have been verified by a credible third party such as the U.S. Pharmacopeia. You can find a list of verified products at uspverified.org.

5. Avoid sex-enhancement products, body­building supplements, and weight-loss aids, the categories that get recalled the most for safety problems. And definitely avoid ingredients known to be dangerous, such as the three above.

Related: The dangers of dietary and nutritional supplements investigated. What you don't know about these 12 ingredients could hurt you.