Does radiation therapy make your hair fall out?

Yes, In area treated: Hair follicles are growing cells. When the hair is radiated the follicle cell stop growing and the hair shaft falls out. Same thing with some chemotherapy drugs. Chemo goes all over so if that type of chemo affects hair then all your hair everywhere falls out. In radiation its the hair that is in the area treated. So for breast cancer for example the arm pit hair on that side will fall out.

Yes, in treated area: Radiation will make hair fall out in the treated area. Depending on the dose, local hairloss can be temporary or permanent.