Tip>> Consult an expert A naturopathic physician (ND) or certified nutrition specialist (CNS) can customize your supplement program, recommend brands and dosages, and make sure you're mixing medications safely, Nevels says. Trained sales consultants at your local natural products store can also help explain labels and offer feedback from other customers.

Tip>> Go online U.S. Food and Drug Administration (FDA) regulations allow only limited information to be printed on a supplement's label, Lieberman says. Independent (and free) online information resources include www.vitasearch.com and www.wholehealthmd.com. For a small fee, you can research specific companies and brands at www.consumerlab.com.

Tip>> Choose the real deal Supplements can be expensive, so shop around for discounts on high-quality brands. But be warned, says Lieberman: If one brand's regular price for a given supplement is substantially lower than that of most other brands, it is probably not of the same quality.