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Vitamin D

Common Name(s)

vitamin D, vitamin D2, vitamin D3

Scientific Name(s)

1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol, alfacalcidol, calcifediol, calcipotriene, calcitriol, cholecalciferol, ergocalciferol, paricalcitol, vitamin D

  • How is this product usually used?

      Vitamin D is generally taken by mouth. It is available in different forms, including chewable tablets and gummies, tablets, capsules, powders, strips, drops, and liquids.

      Vitamin D is listed in both micrograms (µg) and international units (IU). 1 IU of vitamin D is the same as 0.025 µg of vitamin D2 or D3. Vitamin D in supplements is usually shown as IU. Table 1 lists the usual dose and the adequate intake (AI) levels for vitamin D for different age groups. People with vitamin D deficiency might need doses at or above the RDA.

      Table 1. Usual daily dose and AI levels for vitamin D for different age groups.

      Age group

      Vitamin D (IU/day)


      Usual dose range


      0–12 months




      1–3 years



      4–8 years




      9–13 years



      14–18 years




      19–50 years



      51–70 years



      ≥70 years




      14–50 years




      14–50 years



      Depending on your history or medical conditions, your doctor may recommend higher doses of vitamin D (for example, to help prevent/treat osteoporosis, 800 to 1000 IU of vitamin D is generally recommended).

      Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.

  • What is this product used for?

      Vitamin D is important in maintaining overall good health. It helps develop and maintain bones and teeth. It also helps the body absorb and use calcium and phosphorus. Vitamin D taken with calcium is also used to help reduce the risk of developing osteoporosis (a condition where your bones become weak, which increases the risk of fractures). Studies have consistently shown that 800 IU of vitamin D lowers the risk of fractures of the spine, hip, wrist, and leg in adults, which are all complications of osteoporosis.

      At doses at or above the AI, vitamin D supplementation helps to prevent vitamin D deficiency.

      Vitamin D has also been used to treat weak or soft and painful bones, low blood phosphate levels, low blood calcium levels, psoriasis, and rickets. It may also help prevent bone loss in people with chronic kidney failure and help prevent falls.

      There is also research showing that a higher dose of vitamin D supplementation may lower the risk of certain types of cancer. There appears to be a link between low vitamin D levels and colorectal cancer. However, there is limited evidence of benefit in taking vitamin D supplements for breast cancer and no evidence of benefit for prostate cancer. More research is needed to determine the effects of vitamin D on cancer.

      Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

  • What else should I be aware of?

      You should ask a health care professional for information on how much vitamin D you should take, as it may be different depending on your age and what you are using it for.

      Vitamin D is generally well tolerated when taken in recommended doses. High doses of vitamin D over a long period of time can cause weakness, loss of appetite, weight loss, increased urination, irregular heart rhythms, dry mouth, drowsiness, headache, nausea, vomiting, and fatigue. Chronic vitamin D overload can increase blood calcium levels, which can subsequently harden the arteries and damage organs such as the heart and kidneys.

      Medications that can interact with vitamin D supplements include:

      Consult your health care provider if you have concerns.

      Women who are pregnant or breast-feeding can safely take oral vitamin D supplements in recommended amounts (with a maximum of 4000 IU/day). Higher doses might harm the infant. It is safe for infants who are breast-fed to be given vitamin D supplements provided the total amount of vitamin D (from all sources) does not exceed the recommended dose.

      Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.

  • Source(s)
      1. Vitamin D (monograph). Natural Medicines Comprehensive Database. Accessed online 4 July 2012.
      2. Bolvin M. Spotlight on the "sunshine" vitamin. Pharmacy Post; Nov 2007.
      3. Beveridge C. Basic nutrition. In: Repchinsky C, editor. Patient Self-Care. Ottawa: Canadian Pharmacists Association 2002:339-58.
      4. Mayo Clinic. Vitamin D. Accessed 4 July 2012.
      5. Health Canada. Licensed Natural Health Products database. Vitamin D (monograph). accessed 4 July 2014.
      6. Repchinsky C. Compendium of pharmaceuticals and specialties. Ottawa, ON: Canadian Pharmacists Association, 2012.
      7. Bischoff-Ferrari HA, Willett WC, Wong JB et al. Fracture prevention with Vitamin D supplementation: a meta-analysis of randomized controlled trials. JAMA 2005;293:2257-64.
      8. Jackson RD, LaCroix AZ, Gass M et al. Calcium and vitamin D supplement and the risk of fractures. NEJM 2006;354:669-83.
      9. Canadian Cancer Society announces vitamin D recommendations. accessed 4 July 2012.
      10. Skokovic-Sunjic D. Vitamins and the role of the pharmacy technician. Pharmacy Practice: Tech Talk CE May/June 2004.
      11. International Agency for Research on Cancer. Vitamin D and Cancer., accessed 4 July 2012.
      12. Society of Obstetricians and Gynaecologists of Canada. Menopause and Osteoporosis Update 2009. J Obstetrics and Gynaecology Canada. January 2009;31(1):S1-51. . Accessed 14 September 2012.
      13. Papaioannou A, Morin S, Cheung A et al. 2010 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada: summary. CMAJ 2010;doi: 10.1503/cmaj.100771.
      14. Health Canada. Dietary Reference Intakes: Reference Values for Vitamins., accessed 14 September 2012.
      15. Osteoporosis Canada. Vitamin D: An important nutrient that protects you against falls and fractures., accessed 14 September 2012.
      16. Vitamin D. Natural Standard – The Authority on Integrative Medicine. (accessed required). Accessed 04 July 2014
      17. Vitamin D. National Institutes of Health – Office of Dietary Supplements. Accessed 04 July 2014
      18. Vitamin D. MedlinePlus. Accessed 04 July 2014


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