The HCG diet is basically giving someone the pregnancy hormone bHCG or human chorionic gonadotropin (hCG) via injections or drops.  It has been advertised to aid in weight loss but clinical trials fail to support this claim. Among the values claimed for this treatment is the loss of one to two pounds daily, the absence of hunger, and maintenance of muscle tone. Several randomized trials have shown that the hCG diet is not more effective than placebo in the treatment of obesity because an integral component of the hCG diet is a very low calorie diet of about 500 calories/day so of course anyone who does this is going to lose weight.  So they did trials where they compared just doing this versus adding on these pregnancy hormone drops and the addition of the hCG provided no additional effect.