Protocols › Vitamin D

Vitamin D for fractures

Goal: What trials of vitamin D with calcium used to lower the risk of fractures in older adults, and how small the effect was.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 3 Nov 2026
Dose

400 to 800 IU (10 to 20 µg) of vitamin D with 1000 to 1200 mg of calcium a day.[1]

Form

Vitamin D taken together with calcium. Vitamin D alone did not lower the risk of fractures.[1][2]

When to take

Every day. One large dose of 500,000 IU a year raised falls and fractures in older women.[3]

How long

A mean of 5.9 years in the combined trials.[4]

What studies found

In 6 trials with 49,282 older adults, vitamin D with calcium gave 6% fewer fractures and 16% fewer hip fractures.[1] A 2026 review of 15 trials with 51,126 people found 9% fewer fractures and judged it little to no benefit.[2]

Ask a doctor first

Calcium with vitamin D raised the risk of kidney stones by 17% in a 7-year trial of 36,282 women.[4] Thiazide diuretics with vitamin D can raise blood calcium too high.[4] The adult upper limit for vitamin D is 4000 IU (100 µg) a day.[4][5]

Most trials enrolled people at low risk of fractures. People with osteoporosis or a past fracture should ask a doctor or pharmacist first.[2]

References

  1. Vitamin D and Calcium for the Prevention of Fracture: A Systematic Review and Meta-analysis. Yao P, Bennett D, Mafham M, Lin X, Chen Z, Armitage J, et al. JAMA Netw Open, 2019. PMID 31860103
  2. Calcium, vitamin D, or combined supplementation to prevent fractures and falls: systematic review and meta-analysis. Massé O, Mercurio CM, Dupuis S, Al Sahwi M, Arruda A, Dallaire G, et al. BMJ, 2026. PMID 42161415
  3. Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. Sanders KM, Stuart AL, Williamson EJ, Simpson JA, Kotowicz MA, Young D, et al. JAMA, 2010. PMID 20460620
  4. Vitamin D: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  5. Scientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) European Food Safety Authority, 2023. efsa.onlinelibrary.wiley.com