Human Chorionic Gonadotropin more commonly known as HCG, is a hormone produced during pregnancy that signals the body to burn fat to help support the fetus. HCG comes in 5000 IU in 2 different vials. You will mix the vials and administer as your physician has recommended. The HCG diet is very popular as seen on the Doctor Oz show. When HCG is combined with B12 for an energy boost, you can limit your caloric intake to loose weight fast.