HCG is human chorionic gonadotropin, a hormone secreted by cells of the placenta during pregnancy. It was first used as a treatment for obesity by Dr. Simeons in 1954. He combined 125 units of HCG by injection with a 500 calorie diet. After numerous clinical trials showed the lack of effectiveness with the HCG alone, it was not used for many years. Now, however, it has resurfaced in the U.S.
In 1995 a meta-analysis was done of the HCG studies, and it was again found that the evidence was insufficient to claim that HCG altered fat-distribution, hunger reduction, or induced a feeling of well-being. HCG was not shown to be effective for weight loss when used by itself. The 500 calorie diet promoted along with the HCG has been criticized for its low amount of protein. For most patients the protein amount of this diet is lower than the RDA.
There have been no favorable reports on the Simeons method of weight loss since the 1995 meta-analysis. The conclusion by the experts in the field of obesity is that this method of weight loss is ineffective, and the low amount of protein with this diet may be of concern.