How to choose a multivitamin

If you still decide to take a multivitamin, our tests show that you can get a good one for very little money. Use the Ratings, note the nutrient doses, and buy by price. In addition, follow these guidelines:

Avoid megadoses

In general, look for no more than 100 percent of the Food and Drug Administration's Daily Value of the essential vitamins and minerals (one exception is vitamin D, for which the DV is just 400 IU, less than what many people should take). Avoiding big doses is especially important with vitamin A: Just 200 percent of the DV of the retinol form, sometimes listed on labels as vitamin A acetate or palmitate, can increase the risk of birth defects and liver damage.

Look for products that don't exceed about 3,000 IU of vitamin A (2,300 IU for women), or 60 percent of the DV, ideally with at least a third from beta-carotene, the safer form of the vitamin. (Smokers shouldn't take beta-carotene because it may increase their risk of lung cancer.)

Ignore special claims and add-ons

Claims for benefits such as weight control or increased energy are generally unsubstantiated. Even if botanical ingredients, food extracts, and other substances like lutein and lycopene did have a benefit, the amounts in a multivitamin are probably too small to have any effect.

Consider a multivitamin geared to your age or gender

Men's and senior formulas usually don't contain iron, which is good because those groups generally don't need extra iron, and it can lead to organ damage in people with hemochromatosis, a genetic disorder that causes excessive iron buildup. Senior formulas may also contain more vitamin D. Women's vitamins may have some extra calcium, though rarely enough to meet the daily requirement without the need for a separate supplement.