How effective is male homone therapy in treating someone with delayed puberty after age 18? Can I still reach full genital development potential?

Need mor information. Depends upon your your hormone levels. Have you had your chromosomes checked? Might you have klinfelter's? Prognosis for improed pubertal development should be quite good if your circulating blood testosterone levels are low. Would not be the case if you normal or elevated testosterone levels. Good luck.