If you haven't taken a supplement today, chances are you will in the near future. A 2009 Council for Responsible Nutrition (CRN) survey found that 65 percent of American adults regularly take supplements. And according to Nutrition Business Journal research, U.S. sales of dietary supplements grew 6 percent last year—despite the recession. A mounting body of scientific evidence demonstrating the health benefits of supplements has buoyed those sales. Case in point: vitamin D. No doubt you've heard that supplementing with the vitamin—which a staggering 70 percent of American children are deficient in—can strengthen the immune system and help prevent serious health issues such as osteoporosis, certain types of cancer, and high blood pressure.

Still, some reports may leave you feeling that investing in supplements simply isn't worth the cash layout—or worse, the potential health risks. What's more, although supplements are regulated by the U.S. government, some critics contend that current regulation does not do enough to protect consumers (see "U.S. Supplement Regulation," below). "A number of recent episodes have called the quality of dietary supplements into question, such as weight loss supplements containing prescription medications," says John Atwater, PhD, director of verification programs for the United States Pharmacopeia (USP), a Rockville, Maryland-based nonprofit scientific organization that certifies the quality of dietary supplements. In other instances, certain supplements have been found to not contain the amount of nutrients listed on their labels. "These episodes do not represent the industry as a whole," Atwater says. "However, they illustrate the importance of being an informed consumer, and [of] making the right choices for you and your family." Here are five steps to finding the right supplements and trustworthy brands.