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ingestible · for premenstrual syndrome

Calcium Supplementation

Reviewed by the Nimbera editorial team · Last updated May 2026

Thys-Jacobs et al. (n=466) double-blind multicenter RCT: 1200 mg calcium carbonate daily for 3 cycles produced a 48% reduction in total PMS symptom scores vs 30% with placebo (p<0.001 by cycle 3), across all 4 symptom factors. PMID 9731851.$5-$15 per month

How to use

Take 1000-1200 mg elemental calcium (as calcium carbonate with food, or calcium citrate on an empty stomach) daily throughout the month. Split into two doses for better absorption. Vitamin D improves uptake.

How it works

Calcium plays a central role in smooth muscle regulation and neurotransmitter release. Oestrogen fluctuations during the menstrual cycle impair calcium homeostasis; supplementation stabilises intracellular calcium levels, reducing mood symptoms, cramping, and fluid retention.

Where to buy

Pharmacies and supermarkets. Calcium carbonate (e.g. Caltrate, Tums) is cheapest and effective with food. Calcium citrate (Citracal) is better for those with low stomach acid.

Typical cost: $5-$15 per month

Safety notes

Excess calcium (above 2500 mg/day total) is associated with kidney stones and cardiovascular risk. Do not exceed recommended doses. Separate from iron supplements or thyroid medication by 2 hours.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.