Cessation of growth

At the end of puberty hormone levels stabilise. The growth plates at the ends of the long bones in the legs and arms calcify and cease to function. Bones reach their final adult length. This cessation in growth is thought to occur partly in response to the sex steroids that drove the early growth spurts.

Bone growth slows almost completely around 17 or 18 years old for girls and between 19 and 21 years old for boys. However, some bone growth can continue into the person’s early twenties.