Testosterone causes men to grow hair on their face at puberty and later in life they lose hair on the top of their head. Once the hair is in place and growing, Testosterone has little or no noticeable effects. Blocking testosterone will have no effect on facial hair. Blocking Testosterone in later life may prevent losing hair on the top of your head.
Women on the other hand only gain hair growth in the armpits and pubic area after puberty. Estrogens have little effect on hair growth on the top or face of you head.