Drugstore shelves are brimming with shakes, herbs and other products to facilitate weight loss, but the vast majority of them have not been shown to work. A proven medication that helps modestly with weight loss might join their ranks next year.

The pharmaceutical company GlaxoSmithKline has asked the Food and Drug Administration for permission to sell a low-dose version of its diet drug Xenical over the counter. If approved, Xenical would be the first weight loss medication to make the switch from prescription to nonprescription status.

In data presented last week at a national obesity meeting, researchers reported that 36 percent of overweight people taking a low-dose version of Xenical lost more than 5 percent of their initial body weight, compared with 28 percent of people taking a placebo. The researchers also found that users did not abuse the drug by, for instance, exceeding the maximum dose.

The application to sell Xenical over the counter – filed with the FDA in June – reflects the growing concern over American’s obesity epidemic and the need to make a variety of weight-loss tools easily accessible to consumers, says Steven Burton, vice president of weight control for GlaxoSmithKline Consumer Healthcare, a division of the company. About 64 percent of U.S. adults are overweight or obese, and in such a climate, Burton says, it makes sense to market an over-the-counter aid. “People want and need help. … But many consumers, for a variety of reasons, don’t or won’t talk to their doctor about their weight status,” he says.

Xenical, also known by the generic name orlistat, was approved as a prescription diet drug in 1999. The effect of the medication in the marketplace has been modest. Studies show the drug can increase weight loss by 50 percent to 80 percent when used faithfully. For example, a dieter who lost 10 pounds without medication might expect to lose 15 to 18 pounds if taking Xenical.

But the drug doesn’t appeal to all dieters. It works in the gut by inhibiting absorption of dietary fat and can alter bowel habits and cause diarrhea and gas. Xenical can also decrease the absorption of fat-soluble vitamins, and users are advised to take a multivitamin.

“In my experience, the patients for whom Xenical has been effective have been those who say, ‘It keeps me honest. It reminds me if I go off track, I will have a physical consequence,'” says Madelyn Fernstrom, director of University of Pittsburgh Medical Center’s Weight Management Center.