Cost: Pennies a day to budget busting, depending on your appetite
Covered by insurance: Generally not, though some are prescription medicines
Bottom Line: Many work in small dosages, but marketing often pushes the supersize ideaThe FDA says supplements can help ensure that you get necessary nutrients daily. Some may help reduce the risk of diseases such as cancer - though it hasn't been proved by research - but they don't cure disease.
Glucosamine and chondroitin sulfate are a popular supplement combo; athletes take it for joint pain. The research on its effectiveness is mixed, and the cost can reach $1,000 a year or more.
Vitamins are coming under fire these days. In February the Journal of the American Medical Association reported that taking vitamin A and E and beta carotene supplements increases the risk of death. That study, which rolled up the results of multiple trials, is controversial.
What's not is that people who have been gobbling megadoses of supplements in hopes of boosting their immune systems and protecting themselves against cancer aren't doing themselves any favors.
"For some people the drugstore with its walls of vitamins promising health and vitality is even more thrilling than a candy store to a kid," says Michael Parkinson, president of the American College of Preventive Medicine in Washington, D.C.
"And in the case of vitamins especially, they tend to believe that what may be good in small doses must be even better in big doses. That's a dangerous assumption."
Finally, taking supplements to treat serious illness can be dangerous. Type 2 diabetes cannot be controlled with supplements, as some marketers claim.
Undergoing surgery? Tell your surgeon about your supplements and stop taking them two to three weeks in advance.