Protocols › Calcium

Calcium for blood pressure

Goal: What trials of more calcium used in people with normal blood pressure, and how small the drop 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 4 Nov 2026
Dose

A clear effect appeared at 1,000 to 1,500 mg a day, with 1.05 mmHg lower systolic and 2.03 mmHg lower diastolic pressure.[1] Doses under 1,000 mg gave no clear effect.[1]

Form

Supplements or food with added calcium.[1]

How long

A median of 3.5 months in an earlier version of the review.[2]

What studies found

A 2022 Cochrane review of 18 trials with 3,140 people found 1.37 mmHg lower systolic and 1.45 mmHg lower diastolic pressure, with high certainty.[1] In people under 35 the drop was 1.86 and 2.50 mmHg.[1] The trials did not count how many people developed high blood pressure.[1]

Ask a doctor first

The trials did not report side effects.[1] Blood pressure was more than 5 mmHg higher than with placebo in the hours after a large dose.[3] Reviews disagree on whether supplements raise heart risk.[4][5]

People who have high blood pressure or take a medicine every day should ask a doctor or pharmacist first.[2]

References

  1. Calcium supplementation for prevention of primary hypertension. Cormick G, Ciapponi A, Cafferata ML, Cormick MS, Belizán JM Cochrane Database Syst Rev, 2022. PMID 35014026
  2. Calcium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  3. Calcium Supplementation- Efficacy and Safety. Reid IR Curr Osteoporos Rep, 2025. PMID 39937345
  4. Calcium Supplements and Risk of Cardiovascular Disease: A Meta-Analysis of Clinical Trials. Myung SK, Kim HB, Lee YJ, Choi YJ, Oh SW Nutrients, 2021. PMID 33530332
  5. Association Between Calcium Supplementation and the Risk of Cardiovascular Disease and Stroke: A Systematic Review and Meta-Analysis. Sim MG, Teo YN, Teo YH, Syn NL, Li TYW, Yeo LLL, et al. Heart Lung Circ, 2023. PMID 37743221