Calcium citrates

Studies in people

• Benefit

  Calcium absorption after stomach surgery²

  In people who had gastric bypass, calcium citrate got more calcium into the blood than calcium carbonate did.

• Benefit

  Calcium absorption after weight-loss surgery³

  In people who had weight-loss surgery, calcium citrate raised calcium absorption more than calcium carbonate did.

• No harm found

  Bone health after stomach surgery⁴

  In people who had gastric bypass, calcium citrate did not lower parathyroid hormone more than calcium carbonate.

• Open question

  Bone breakdown⁶

  In young women, calcium citrate lowered parathyroid hormone and raised blood calcium, but its effect on bone breakdown was not significant.

• Open question

  Heart risk from calcium⁷

  Scientists do not yet know whether calcium citrate raises heart risk, though it briefly lifts blood calcium more than dairy does.

• No harm found

  Kidney stone risk⁸

  In postmenopausal women, calcium citrate did not raise the risk of kidney stones forming.

• Open question

  Calcium absorption into the blood⁹

  In people, calcium citrate raised blood calcium levels only slightly more than a placebo did.

• Concern

  Aluminum absorption from food¹¹

  Calcium citrate raised aluminum levels in healthy women, but scientists do not yet know if long-term use builds it up.

• No harm found

  Aluminum buildup in the body¹²

  In people with kidney problems and normal women, calcium citrate did not change aluminum levels.

• Benefit

  Bone breakdown in older women¹³

  In older women, calcium citrate lowered markers of bone breakdown more than calcium carbonate did.

Animal and lab studies only

• Open question

  Bone loss in space¹⁴

  In rats, calcium citrate with collagen peptide did not stop bone loss from simulated weightlessness, though it partly helped bone structure.

How it’s made and used

• Blood calcium levels⁵

  Calcium citrate raised calcium in the blood for hours after each dose, and this stayed the same after three months.

• Calcium absorption from juice¹⁰

  In women, calcium citrate malate in apple juice was absorbed better than in orange juice.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Expert panels that weigh all the research. Shown for context: the signal at the top does not count them.

• UN and WHO food additive experts (JECFA), 1973

  No daily limit needed (“ADI not specified”, JECFA’s term for very low toxicity).