HCG stands for "human chorionic gonadotropin" and it is the hormone you look for with a pregnancy test. It stimulates your fat deposits to be broken down for use as energy, working well for both men and women. Treatment cycles last from 26 - 43 days andyou may lose 20 - 30 lbs or more each cyle. Cylces may be repeated, with increasing interval time between them until you reach your ideal weight. The most important part is the diet, which is very restrictive (500 calories per day) but surprisingly easy to comply with because the HCG liberates roughly a pound of fat per day which provides you with another 3000 calories or more to use for energy and nourishment. For extensive inormation about HCG protocols go to hcgdietguru.com. On a side note, feel free to deviate from the program in various ways, but results may not be as good.