When are you too old to take hgh injections like humatrope (human growth hormone) to gain height?

When epiphyses close: The long bones involved in height have a shaft (diaphysis), flare end (metaphysis), and epiphysis (end cap of bone). When the epiphysis closes, the bone length will no longer respond to heightening growth. But it is not a precise science. Two main bones that affect height are femur and tibia. Each one can close anywhere from age 15 to 22. Soc needs to see x-rays, growth curves and take full hx.