It alters the cycle of bone formation and breakdown in the body. Alendronate slows bone loss while increasing bone mass, which may prevent bone fractures. Alendronate is used in men and women to treat or prevent osteoporosis that is caused by menopause or by taking steroids.Alendronate is also used to increase bone mass in men who have osteoporosis, and to treat Paget's disease of bone in men and women.Alendronate may also be used for purposes not listed in this medication guide.lendronate is also used to increase bone mass in men who have osteoporosis, and to treat Paget's disease of bone in men and women. Alendronate may also be used for purposes not listed in this medication guide.