This invention provides a method of treating, preventing, suppressing, inhibiting, or reducing the risk of developing a bone-related disorder, for example osteoporosis, osteopenia, increased bone resorption, bone fracture, bone frailty and/or loss of bone mineral density (BMD), by administrating a therapeutically effective amount of a selective androgen receptor modulator (SARM) and/or its analogue, derivative, isomer, metabolite pharmaceutically acceptable salt, pharmaceutical product, hydrate, N-oxide, or any combination thereof. The invention also provides methods of decreasing fat mass (FM) and increasing lean mass, comprising administering same.