Calcium is the main mineral in bone. Adults need roughly 1,000 to 1,200 mg a day, and most can get it from food. Calcium supplements, usually with vitamin D, can reduce bone loss and fractures in people at high risk or who are deficient, but evidence for routine use in healthy people is weaker, and high doses carry risks. Calcium does not treat back pain.
Check with a doctor or pharmacist if you take other medicines, have kidney disease, are pregnant, or are being treated for osteoporosis. Supplements interact with medicines and can be harmful in excess. See supplement safety.
How much you need
| Group | Recommended daily amount | Upper limit (all sources) |
|---|---|---|
| Adults 19 to 50 | 1,000 mg | 2,500 mg |
| Men 51 to 70 | 1,000 mg | 2,000 mg |
| Women 51 and over | 1,200 mg | 2,000 mg |
| Everyone 71 and over | 1,200 mg | 2,000 mg |
Figures from the NIH Office of Dietary Supplements.1
Food first
Dairy products, fortified plant drinks, tofu set with calcium, canned fish with bones, and some leafy greens are good sources. Food also brings protein and other nutrients bone needs, and calcium from food is absorbed more gradually than a large supplement dose.
What supplements do
A 2026 review of supplements for bone health concluded that calcium and vitamin D reduce bone loss and fracture risk in selected groups, such as older adults, people in care homes and those with documented deficiency, while evidence is less consistent in the general population.2
The largest trial, the Women’s Health Initiative, gave 36,282 postmenopausal women 1,000 mg of calcium with 400 IU of vitamin D or placebo for about seven years. Hip fractures were 12% lower, a difference that could have been chance, while kidney stones were 17% more common.3
Calcium and back pain
Calcium has no proven effect on common back pain. It matters for the spine through bone strength, especially in later life; see osteoporosis of the spine and how the spine changes with age.
If you take a supplement
- Count what you already eat; many people need only a small top-up, if any.
- Split doses over 500 mg, and take calcium carbonate with food.
- Stay under the upper limit from all sources combined.1
- Calcium works with vitamin D; see also vitamin K2 and magnesium.
Footnotes
General information, not medical advice. Every claim carries its source; where the evidence is thin, the page says so.Editorial policy · How we grade evidence · All sources · Disclaimer