The Mayo Clinic advises that adult women take 200 IU of vitamin D3 per day, and recommends that daily intake not exceed 2000 IU. According to research studies reported in the Journal of Clinical Endocrinology and Metabolism, Vitamin D3 is more effective in humans than Vitamin D2.

On the Other: New Research

The Vitamin D Council suggests that the current recommendations for Vitamin D in general are insufficient. The Council recommends that adult women take 1000 IU of vitamin D3 for every 25 pounds of their body weight. For someone of average weight this would equal about 5000 IUs per day.

Bottom Line

Vitamin D3 is manufactured within the body as a response to sunlight exposure, and is also found in cheese, cream, butter, margarine, fish, oysters and fortified milk and cereal. Inadequate amounts of vitamin D3 can lead to osteoporosis in women. Women who get regular exposure to sunlight may not need to take extra vitamin D3 supplements; however, those who get little sun exposure will likely need to take a multivitamin or vitamin D3 supplement to avoid a vitamin D deficiency.

Source:

Vitamin D Council

NIH: Vitamin D

Mayo Clinic: Vitamin D

Resource:

Mayo Clinic: Osteomalacia

Vitamin D3 Research