Prolia (denosumab) is a prescription medication used to treat osteoporosis and reduce bone loss. Prolia comes as a liquid solution in a prefilled syringe, with each syringe containing 60 milligrams of the drug. Typically, Prolia is injected once every 6 months, with each injection containing 60 milligrams. The injections are usually administered by a doctor under the skin of the belly, upper arm, or thigh. Your doctor may also recommend taking supplements containing calcium and vitamin D while you are receiving Prolia. Prolia is considered a safe and effective option for long-term treatment. If you have any questions about the injections, it is best to consult your doctor.