Calcium

Evidence ratingHigh

A key bone mineral. In a meta-analysis of postmenopausal women, calcium supplementation was reported to significantly slow bone mineral density loss at the spine and femur, with the greatest benefit in those with low dietary intake and when combined with vitamin D. High supplemental doses (over 1,000 mg/day) have been linked in some studies to cardiovascular risk.

A well-studied, foundational ingredient

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Effects reported in research

Reported to slow bone density loss in postmenopausal women, especially those with low dietary intake

Tends to work better for bone outcomes when combined with vitamin D

Helps cover a dietary shortfall of this mineral

Dosage & timing

Adult intake guidance is roughly 600–800 mg/day.
Use it to fill a dietary gap, ideally split into doses of 500 mg or less for absorption.
Combining with vitamin D is reported to improve uptake.

Cautions

•High supplemental doses (over 1,000 mg/day) have been linked in some studies to higher cardiovascular risk, a pattern not typically seen with dietary calcium.
•It can interfere with the absorption of iron and some medications, so separate the timing.
•People with kidney disease, hypercalcemia, or on medication should consult a doctor.
•This site is for educational reference only.

Supporting research

Meta-analysis

Calcium supplementation and bone mineral density in postmenopausal women: a meta-analysis

Endocrine Reviews, 2002

A meta-analysis examining the effect of calcium supplementation on bone mineral density (BMD) in postmenopausal women. Calcium supplementation significantly attenuated BMD loss at the spine and hip. Co-supplementation with vitamin D tended to enhance benefits. Effects were greatest in populations with low baseline calcium intake. However, excessive intake may be associated with cardiovascular risks, so adherence to upper intake levels is recommended.

View study details

Last checked: 2026-06-25