Male bodybuilders used HCG for another important reason. It is almost exactly the same amino acid sequence as Luteinizing Hormone (LH).
The Leydig cells then produce androgens such as testosterone. Obviously this means so-called natural bodybuilders reported use of HCG to increase endogenous (natural) testosterone levels. According to some clinical studies this works so well that an injection of 1500-2000 i.u. of HCG has increased plasma testosterone levels 200-300% over normal levels. For those males who utilized high aromatizing AAS, HCG was a “partial” cure for restarting natural testosterone production either mid or post-cycles