Vitamin D is used to treat hyperparathyroidism, a disorder that causes weak bones, bone pain, and bone loss, as well as the disease rickets, which is brought on by a lack of vitamin D in the body.

- used to prevent bone loss and low calcium in those with kidney failure, as well as falls and fractures in those at risk for osteoporosis
-is used for conditions affecting the heart and blood vessels, such as high blood pressure and high cholesterol -also used for diabetes, obesity, muscle weakness, multiple sclerosis, rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), asthma, bronchitis, premenstrual syndrome (PMS), tooth and gum disease -is used for boosting the immune system, preventing autoimmune diseases.