"That usually creates a buzz, and people want to come in and get the newest and the latest," said Keith Mercer, vitamin consultant.
"A supplement, by definition, means in addition to, not instead of. There's sort of a myth surrounding supplements that they're benign and that they're healthy for us," says Susan Hewlings, PhD, assistant professor at UCF College of Medicine in Orlando.
Mega-dosing on fat-soluble vitamins like A, K, E and D, can be dangerous, leading to bone and liver damage.
"There may be plenty of people in our population that would benefit from a vitamin D supplement. That's not to say mega-dosing on vitamin D is a good idea," said Dr. Hewlings.
What about multivitamins?
"A multivitamin is a way to cover your bases," said Dr. Hewlings.
Other experts disagree. One recent national women's study found taking multivitamins did nothing to reduce the rate of major diseases like cancer, heart disease and stroke.
Believers say the evidence is in how they feel. But until everyone agrees, experts say do your research.
"Consumers beware. Right now, supplements are not regulated by the FDA. You want to see the data, and you want to see the numbers," says Dr. Hewlings.