I'm 22 male.i've white hair, so using color, don't know but now my hair is very dry & thing and facing heavy hair loss.what should i do, any medicine?

Hormone imbalance: Have your doc check your thyroid, this can cause hairloss and dry hair. Especially if you have issues with feeling cold/constipation and fatigue. Certain haircolors can also cause the hair to dry out and thin; be careful with what you use. Ask your professional hair dresser for help! some people go bold earlier then others; there could be a genetic factor there as well, hormonal or dermatologic.