Protocols › Calcium

Calcium for premenstrual syndrome

Goal: What trials of calcium used to ease premenstrual symptoms, and how strong the evidence is.

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

1,200 mg of calcium a day in the largest trial.[1] Smaller trials gave 1,000 mg of calcium carbonate a day.[2][3]

Form

Calcium carbonate.[1]

How long

3 menstrual cycles in the largest trial, with lower symptoms by the second cycle.[1]

What studies found

In 466 women, symptoms fell by 48% with calcium and 30% with placebo by the third cycle.[1] A 2025 review of 31 trials of nutrition found consistent benefits on mood symptoms with calcium, but only 1 trial had a low risk of bias.[4] A pilot trial in 39 women found a small effect of calcium, much smaller than of fluoxetine.[5]

Ask a doctor first

Calcium carbonate can cause gas, bloating and constipation.[6] It can lower the absorption of levothyroxine, and other medicines also interact with calcium.[6]

People who take a medicine every day should ask a doctor or pharmacist first.[6]

References

  1. Calcium carbonate and the premenstrual syndrome: effects on premenstrual and menstrual symptoms. Premenstrual Syndrome Study Group. Thys-Jacobs S, Starkey P, Bernstein D, Tian J Am J Obstet Gynecol, 1998. PMID 9731851
  2. Calcium supplementation in premenstrual syndrome: a randomized crossover trial. Thys-Jacobs S, Ceccarelli S, Bierman A, Weisman H, Cohen MA, Alvir J J Gen Intern Med, 1989. PMID 2656936
  3. Effects of calcium supplement therapy in women with premenstrual syndrome. Ghanbari Z, Haghollahi F, Shariat M, Foroshani AR, Ashrafi M Taiwan J Obstet Gynecol, 2009. PMID 19574172
  4. Effect of nutritional interventions on the psychological symptoms of premenstrual syndrome in women of reproductive age: a systematic review of randomized controlled trials. Robinson J, Ferreira A, Iacovou M, Kellow NJ Nutr Rev, 2025. PMID 38684926
  5. A pilot study to compare fluoxetine, calcium, and placebo in the treatment of premenstrual syndrome. Yonkers KA, Pearlstein TB, Gotman N J Clin Psychopharmacol, 2013. PMID 23963058
  6. Calcium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov