Vitamin D3 is a fat soluble vitamin. Vitamin D3 is used to prevent and treat rickets, weak bones (osteoporosis), bone pain, bone loss in people diagnosed hyperparathyroidism and an inherited condition known as osteogenesis imperfecta in which the bones become brittle and easily broken.
Vitamin D3 is also used to prevent bone fracture in people with a higher risk of osteoporosis as well as bone loss in people with kidney failure. Vitamin D3 drops are given to bread-fed infants to supplement the low levels of the vitamin in breast milk. Vitamin D3 works by helping the body absorb calcium and phosphorous.