Examine the packed multivitamin aisle and it's immediately apparent that the days of the one-size-fits-all supplement are dwindling. Although multivitamins remain the best-selling dietary supplement category, constituting 18.9 percent of the supplements market in 2007, according to Nutrition Business Journal, the category has seen better days. In April, Chicago-based global research company Mintel projected that vitamin and mineral sales across all channels to drop 1.9 percent this year as consumers trade down or do without.

There is an exception, however. "Brands that have a strong history and dedication to the natural channel, as well as very clean ingredient profiles continue to perform well," says John Pavlenkov, a business consultant for market research company SPINS, based in Schaumburg, Ill. "Companies that are focusing on particular segments of the population, such as men, women or seniors also seem to be doing well."

Based in Brattleboro, Vt., New Chapter, which offers gender-specific multivitamins, was the top-selling multivitamin brand in the natural channel in the past year. Garden of Life, based in West Palm Beach, Fla., which launched a raw age- and-gender specific line in 2008, saw a 175 percent spike in sales, according to SPINS. Maximize the trend in your store and help your customers choose the best-fitting multi with these gender- and age-specific tips.

Women
Premenopausal women should look for a multivitamin that contains supplemental iron because iron is flushed out during menstruation, says Victoria Drake, Ph.D., a research associate at the Linus Pauling Institute in Corvallis, Ore. Meanwhile, men and postmenopausal women typically get and retain enough iron from food sources. Women of childbearing age also need folate (important for preventing neural tube defects) and vitamins A, C and D; calcium and magnesium (for bone health). They may also benefit from hormone-regulating minerals and herbs, such as zinc, chasteberry, maca root or black cohosh, says Marcus Laux, a naturopathic doctor in Las Vegas.

Men
Unless he is vegetarian, a man probably shouldn't take a multivitamin with extra iron in it because it may cause oxidative damage to tissues and lead to disease, Drake says. However, he should consider a multivitamin with nutrients aimed at promoting prostate health (lycopene and saw palmetto) and heart health (coenzyme Q10). Men's multivitamins also often include herbs associated with virility, such as schizandra and maca.

Seniors
Drake says that because senior citizens have a harder time metabolizing vitamin B12, a critical nutrient for neurological and cardiovascular health, it's important for them to look for it in a multivitamin, along with calcium and magnesium to support strong bones. Formulas for people age 50 and older also often contain vitamins B, C and D to preserve memory and concentration; antioxidants such as cinnamon and fenugreek to fight age-related diseases triggered by free radical damage; and herbs such as chamomile and lavender to combat stress. However, multis usually don't contain enough calcium, so Drake recommends that seniors take an additional calcium supplement.

Writer Lisa Marshall is a mother of four, who would love to have a "one size fits all" for her entire family.

Beyond the multi:

Three hot supplements

> Resveratrol
Found in the skin of red grapes, berries and Japanese knotweed, this polyphenol antioxidant is believed to have a similar effect on cells as calorie-restriction does: It activates proteins called sirtuins, which fend off oxidative stress and repair DNA. A 2008 study by the National Institute on Aging found that mice fed resveratrol showed "a marked reduction in signs of aging," including improved heart health, motor coordination and bone density, as well as fewer cataracts. Few human studies exist, and because resveratrol is rapidly metabolized and flushed out of the body, finding an effective form has proved tricky. Look for "transresveratrol" the most-studied and best-absorbed form available to date.

Resveratrol may mimic estrogen, so women with a history of breast or ovarian cancers should avoid resveratrol supplements.

> Vitamin D
In the fall of 2008, the American Academy of Pediatrics upped its recommendations for vitamin D intake in children to 400 IU, and the Institute of Medicine launched a study, due out in 2010, to re-evaluate recommendations for adults. The vitamin has been linked to immunity and reduced risk of cancer, diabetes, heart problems and other illnesses, according to the AAP. Sunlight is humans' primary source of vitamin D, but increased fears about skin cancer—and the resulting widespread use of sunscreen—has prompted concerns that many people aren't getting enough. Cat Pantaleo, nutritionist for Pharmaca Integrative Pharmacy, based in Boulder, Colo., recommends D3 (cholecalciferol) supplements because of evidence suggests it is more easily utilized by the body than D2.

> Sulforaphane
This powerful antioxidant, found in cruciferous vegetables, is creating quite a buzz among antioxidant researchers, who say it has the ability to ignite the body's internal system for creating its own antioxidants. It's also a potent detoxifier. One study published in the journal Cancer Research in 2008, found that mice fed sulforaphane were less likely to contract bladder cancer. Another, conducted by Johns Hopkins researchers in 2007, found that when sulforaphane was applied to the mice's skin, they were less likely to contract skin cancer. Sulforaphane is available in tea, sprouts and supplements.