They claim it gives an instant energy high, that it lasts for 48 hours. And there's no crash after it wears off. The substance is vitamin B 12, taken up the nose in gel form. Snorting has great appeal for those who used to inhale unhealthy stuff, and now they can still practice the ritual.

Vitamin B12 is found in meat and dairy products, and a minuscule amount (3 micrograms per day) is needed to prevent pernicious anemia. But since the 1940s it has had a reputation—medically unfounded—of providing energy.

Now believers in B12 megadosing are cramming their nostrils with Ener-B, the gel form sold at health food stores by Nature's Bounty Inc. of Bohemia, N.Y. Each dose contains 400 micrograms of B12. But why up the nose? "By snorting it, B12 goes directly into the bloodstream," claims Denise Buz Buzian, owner of Au Naturel, a San Francisco health food store. Adds customer Maggie Hallahan: "I get twice as much work done since taking Ener-B."

Doctors say putting B12 up your nose is about as helpful as rubbing it between your toes, though it's unlikely to do much harm either. "It's ridiculous, but humans never surprise me," says Dr. Suzie Harris at the U.S. Department of Agriculture. "Somebody's making money someplace."