Commission official Vicki Streitfeld declined to confirm whether Cellasene is under investigation. Typically, the agency does not publicly say whether it is investigating a company. Debbie DeSantis, vice-president of the pill's Italian manufacturer, Medestea Internazionale, also wouldn't say whether regulators are reviewing the product.

Cellasene entered the U.S. market in early March, making a big splash on the advertising pages of fashion magazines and flying off the shelves in some drug stores with its claims of reducing cellulite - the pesky pockets of fat that cause the area around women's hips and thighs to appear dimpled.

The pills, available at major drug and retail stores, cost about $70 for a two-week supply in Canada. Vitamin maker Rexall Sundown Inc., based in Boca Raton, Fla., has the U.S. distribution rights to Cellasene.