Men with idiopathic hypogonadotrophic hypogonadism typically have unusually small penises. A Korean study found that administering human chorionic gonadotropin (hCG; 1,500-2,000 IU, three times per week for 24 weeks) increased blood testosterone, penis length and testicular size. HCG stimulates the testes to produce testosterone. It is a popular supplement among some bodybuilders. It is doubtful that hCG will increase penis size in healthy young men with normal testicular function. (Chonnam Medical Journal 47:39-42, 2011)