My identical twin was diagnosted with breast cancer and underwent a masectomy. After she completed her chemotherapy and radiation treatments, her hair grew back and looked normal. But since then she has taken Arimidex and Alopecia and she is experiencing significant hair loss. It is important to note that we still look very much alike except for the fact that her hair is now very thin whereas mine is still quite thick and full. Hair loss is not listed as an Arimidax side affect.