Know safety concerns

A product isn't safe simply because it's natural. Though rare, some dietary supplements have been linked to serious problems, such as liver damage.

Supplements can have strong effects. Ephedra (ma-huang) is an herb once used for weight loss. The FDA banned it because of its link to side effects, such as high blood pressure, irregular heart rate, stroke, seizures and heart attacks.

Some weight-loss supplements have been found to have ingredients that aren't listed on the label, such as prescription medicines. These can be harmful.

Other safety issues may include having an allergy to something in the supplement and interactions with other medicines you take.