Transformations for trans-gendered people, do they have to take hormones for life?

Hormone Replacement Therapy is a lifelong commitment. Not only to sustain appearances, but to give the body things that it needs. Specifically in regards to bone, both estrogens and androgens are responsible for bone growth and health. To do without them can be extremely detrimental. For example, if a female to male transguy were to have had his ovaries removed and stop taking testosterone, his body would no longer have appropriate hormone levels to fight osteoporosis.