The most common use for large doses of vitamin D2, also known as ergocalciferol, for treating and preventing bone disorders and bone loss, states WebMD. In conjunction with other medications, D2 is also used to treat hypothyroidism and some forms of kidney disease. The Mayo Clinic reports that, as of 2010, the recommended daily allowance, or RDA, of vitamin D for people ages 1 to 70 is 600 international units, commonly referred to as IUs.
In addition to treating parathyroid and bone disorders, large doses of D2 are often used for treating heart disease; managing osteomalacia induced by anti-seizure medications; improving cognitive function; preventing falls from loss of balance; and preventing fractures, according to the Mayo Clinic. It has also been taken for increased longevity; muscle pain or weakness; and type two diabetes. The Mayo Clinic notes that doses are often combined with other medications or as part of a full-spectrum vitamin D supplement and are only administered over specific lengths of time. Vitamin D2 is also used to treat vitamin D deficiency and low blood calcium levels, says WebMD.
When considering large doses of vitamin D2, it is important to consult with a physician or other health care provider.