“Calcium supplements prevent fractures in adults.”
For most adults, calcium supplements do not meaningfully prevent fractures.
A healthy adult living at home is unlikely to prevent a fracture by taking a calcium pill. Calcium that is part of an osteoporosis treatment plan set by your clinician is a different situation, so do not stop it on your own.
If you take calcium only to prevent fractures, ask your clinician or pharmacist at your next visit whether you still need it.
Safety note: Calcium supplements can cause constipation, upset stomach and belching. In a large trial of 36,282 women followed for about 7 years, 2.5% of women taking calcium plus vitamin D reported a kidney stone, compared with 2.1% on a placebo pill (about 1 extra stone for every 270 women). Calcium can make other medicines work less well. Take it at least 4 hours apart from thyroid medicine (levothyroxine), and ask your pharmacist how far apart to take it from your other medicines, because some need a longer gap; for example, the antibiotic ciprofloxacin should be taken at least 2 hours before or 6 hours after calcium.
Talk to a healthcare professional if: you take osteoporosis medicine, thyroid medicine or other daily medicines, you have had kidney stones, or you have been told you have low bone density or a high risk of fractures.
Two large reviews of randomized trials find that calcium pills alone make little or no difference to fracture risk, and the small benefit seen in some trials fades in the best-run ones and comes mostly from one trial in very frail nursing-home residents. Confidence is Moderate, not Strong, because evidence for frail, high-risk people is thin.
For most adults, calcium supplements do not meaningfully prevent fractures. In a 2026 review of 11 trials with about 9,000 people, 9.9% of people taking calcium alone had a fracture, compared with 10.9% of people not taking it, a gap small enough to be due to chance. Calcium taken with vitamin D lowered fractures by about 1 percentage point, which the review judged too small to matter and which came mostly from one trial in a very high-risk group.
An earlier review of 26 trials found a small drop in fractures overall (about 11% lower relative risk). But the drop disappeared in the 4 best-run trials, which included 44,505 people, and there were signs that positive studies were more likely to be published. Neither review found a clear drop in hip fractures from calcium.
Most of these trials studied people living at home (87% of trials) who were not at high risk of fractures (73% of trials). People taking osteoporosis medicines were not included in the 2026 review. Evidence for people in nursing homes or at very high risk is limited. One trial in frail older women in residential care, who got little calcium and vitamin D, did find fewer fractures.
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