The U.S. Food and Drug Administration and the Federal Trade Commission, as well as government agencies in all 50 states, regulate dietary, or nutritional, supplements. Still, consumers are wise to pay attention to what’s in their daily multivitamin/mineral formula or any other supplement they take.

Read all “Supplement Facts” carefully and follow directions. Here’s what to look for (and what it means).

• Serving Size is the amount the supplement manufacturer recommends you take each day. (Don’t take higher amounts, except on the advice of a healthcare provider.)
• Expiration date is the recommended cut-off date for full potency. Expired supplements—though unlikely to cause harm—may provide little to no benefit and are best replaced.
• Amount Per Serving heads the list of nutrients found in each supplement, followed by the quantity.
• %DV (Percent Daily Value) shows what percentage of the recommended daily intake each nutrient provides.
• (* Asterisk indicates that Daily Value has not been established.)
• IU (International Unit) is a standard measurement for fat-soluble vitamins. Milligram (mg) and microgram (mcg) are typical measurements for water-soluble vitamins and minerals: 1 milligram = .001 gram; 1 microgram = .001 milligram.
• Storage recommendations help consumers keep products effective. While most recommend storing in a cool, dry place, some supplements (like fish oil) may require refrigeration after opening.
• Manufacturer’s or distributor’s name, address, and zip code are required on all labels. (Don’t hesitate to contact the company if you have questions about a supplement.)
• Ingredients list includes nutrients and other substances used to formulate the supplement, starting with the most prominent by weight and decreasing in order to the least prominent. (Vegetarians can read whether animal byproducts are used in supplement manufacture.)