According to published studies, some ingredients in the Hydroxycut formula may help obese patients lose up to 4.5 times the weight than they would with just diet and exercise alone. This is supported by two 8-week studies in which all groups followed a diet and exercise plan, subjects using ingredients similar to those in Hydroxycut lost, on average, significantly more weight than subjects who were using a placebo (14.99 vs. 3.06 lbs and 12.54 vs. 3.53 lbs).

Hydroxycut promotes itself as being created and endorsed by doctors. Television advertisements for Hydroxycut feature Jon Marshall, a graduate of Midwestern University’s osteopathic medical school, still in residency. Hydroxycut is also endorsed by Marvin Heuer, Associate Clinical Professor in the Department of Family Medicine and Community Health at the University of Florida, formulator of Hydroxycut, and Chief Scientific Officer of Iovate Health Sciences, the company that markets the product.

In recent years, Hydroxycut has become available in several forms and formulas. All the versions have been made ephedra-free and include:

Hydroxycut
Caffeine-Free Hydroxycut – similar to regular Hydroxycut but designed for caffeine-sensitive people.
Hydroxycut 24 – an around-the-clock type of weight-loss product that includes regular Hydroxycut for the daytime and the caffeine-free for the evening.
Hydroxycut Hardcore – a weight-loss supplement for bodybuilders or other sportspersons.
Hydroxycut Max! – a weight-loss supplement for female fitness competitors or other sportswomen.

Source: http://en.wikipedia.org/wiki/Hydroxycut