It could be a late night infomercial - a magical caffeine cream that slenderizes thighs.

But a new study in the Journal of Cosmetic Dermatology reports just that - Brazilian researchers studied 99 women treated with a cream consisting mostly of a 7 percent caffeine solution. The women used the cream twice daily for 30 days.

When the researchers took their subjects’ measurements at the end of the study, the slimming effect was clear. More than 80 percent of the women had a reduction in the circumference of their upper and lower thighs. Nearly 68 percent also reduced their hip measurements.

Whether caffeine banishes cellulite is less clear. The researchers assessed cellulite changes with a handheld imaging instrument that reveals microcirculation in fat tissue. Imaging showed little change in cellulite even in the hips and thighs that slimmed down. The researchers speculate that the 30-day trial might not have been long enough for the cream to act on cellulite.

“This is no cure for cellulite”, said lead researcher Omar Lupi of the Federal University of then State of Rio de Janeiro. “But it can help women who want to look thinner. Exercise is still the best way to go.”

This study is published in the Journal of Cosmetic Dermatology.