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The following doses have been studied in scientific research:
ADULTS
BY MOUTH:
- For vitamin D deficiency: 50,000 IU per week for 6-12 weeks has been used. However, some patients require higher doses for longer periods of time to maintain optimal blood levels of vitamin D.
- For preventing osteoporosis: 400-1000 IU/day of vitamin D in a form known as cholecalciferol has been used in older adults. Usually it is taken along with 500-1200 mg of calcium per day. Some experts recommended higher doses of 1000-2000 IU daily, and 0.43-1.0 mcg/day of calcitriol have been used for up to 36 months.
- For preventing bone loss due to use of corticosteroids: 0.25-1.0 mcg/day of vitamin D in forms known as calcitriol or alfacalcidol have been used for 6-36 months. In many cases, these forms of vitamin D are used along with calcium. Also, 50-32,000 mcg/day of vitamin D in the form of calcifediol has been used for 12 months. Finally, 1750-50,000 IU of vitamin D has been taken in daily or weekly doses for 6-12 months.
- For heart failure: 800 IU/day of vitamin D in a form known as cholecalciferol has been taken alone or along with 1000 mg/day of calcium for 3 years. 400 IU/day of vitamin D in a form known as cholecalciferol has been taken with 1000 mg/day of calcium in postmenopausal women.
- For bone loss caused by having too much parathyroid hormone (hyperparathyroidism): 800 IU/day of vitamin D in a form known as cholecalciferol has been used for 3 months.
- Multiple sclerosis (MS): 400 IU/day of vitamin D has been used to prevent MS.
- For preventing respiratory tract infections: 300-4000 IU of vitamin D in a form known as cholecalciferol has been used for 7 weeks to 13 months.
- For preventing tooth loss in the elderly: 700 IU/day of vitamin D in a form known as cholecalciferol has been taken in combination with calcium 500 mg/day for 3 years.
APPLIED TO THE SKIN:
- For a specific type of psoriasis called plaque psoriasis: A form of vitamin D known as calcipotriol has been applied to the skin alone or along with corticosteroids for up to 52 weeks. Typically calcipotriol is gen at a dose of 50 mcg/gram. Specific products used in clinical studies include Daivobet and Dovobet. These products contain 50 mcg/gram of calcipotriol and 0.5 mg/gram of betamethasone dipropionate.
AS A SHOT:
- For vitamin D deficiency: 600,000 IU of vitamin D (Arachitol, Solvay Pharma) given as a single shot into the muscle has been used.
CHILDREN
BY MOUTH:
- For preventing respiratory tract infections: 1200 IU/day of vitamin D in a form known as cholecalciferol has been given to school-aged children during the winter to prevent the flu. Also, 500 IU/day of cholecalciferol has been used to prevent worsening of asthma symptoms caused by respiratory tract infections.
Most vitamin supplements contain only 400 IU (10 mcg) vitamin D.
The Institute of Medicine publishes recommended daily allowance (RDA), which is an estimate of the amount of vitamin D that meets the needs of most people in the population. The current RDA was set in 2010. The RDA varies based on age as follows: 1-70 years of age, 600 IU daily; 71 years and older, 800 IU daily; pregnant and lactating women, 600 IU daily. For infants ages 0-12 months, an adequate intake (AI) level of 400 IU is recommended.
Some organizations are recommending higher amounts. In 2008, the American Academy of Pediatrics increased the recommended minimum daily intake of vitamin D to 400 IU daily for all infants and children, including adolescents. Parents should not use vitamin D liquids dosed as 400 IU/drop. Giving one dropperful or mL by mistake can deliver 10,000 IU/day. The US Food and Drug Administration (FDA) will force companies to provide no more than 400 IU per dropperful in the future.
The National Osteoporosis Foundation recommends vitamin D 400 IU to 800 IU daily for adults under age 50, and 800 IU to 1000 IU daily for older adults.
The North American Menopause Society recommends 800 IU to 1000 IU daily for all.
Guidelines from the Osteoporosis Society of Canada recommend 400-1000 IU of a specific form of vitamin D called cholecalciferol for people up to age 50, and 800-2000 IU per day for people over 50.
The Canadian Cancer Society recommends 1000 IU/day during the fall and winter for adults in Canada. For those with a higher risk of having low vitamin D levels, this dose should be taken year round. This includes people who have dark skin, usually wear clothing that covers most of their skin, and people who are older or who don't go outside often.
Many experts now recommend using vitamin D supplements containing cholecalciferol in order to meet these intake levels. This seems to be more potent than another form of vitamin D called ergocalciferol.
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Unit Conversion *
1 IU = 0.025 mcg ergocalciferol (Vitamin D2)
1 IU = 0.025 mcg cholecalciferol (Vitamin D3)
