Strontium ranelate, marketed under the trade name Protelos, is a prescription drug used in the treatment of osteoporosis to reduce the risk of vertebral and hip fractures in postmenopausal women and derives from the chemical element strontium. It is different than other osteoporotic treatments in that it works to both promote bone formation and reduce bone resorption. In other words, strontium ranelate helps bones grow and reduces bone loss.
Strontium is very similar to calcium. Its nucleus is nearly the same size as calcium. Because of this, the body very easily absorbs strontium. There’s also some research that suggests the body metabolizes strontium similarly to calcium.