Skip to content
Back to Premenstrual Syndrome

ingestible · for premenstrual syndrome

Magnesium Glycinate or Oxide

Reviewed by the Nimbera editorial team · Last updated May 2026

Walker et al. (n=38) double-blind crossover RCT: 200 mg magnesium oxide daily for 2 cycles produced significantly greater reduction in PMS-H symptoms (weight gain, bloating, breast tenderness, swelling) vs placebo in cycle 2 (p=0.009). PMID 9861593.$10-$25 per month

How to use

Take 200-400 mg of elemental magnesium (as glycinate for better tolerance, or oxide) daily with food, throughout the month. Effects on fluid retention symptoms build after 4-8 weeks of consistent use.

How it works

Magnesium acts as a physiological calcium antagonist and regulates aldosterone-mediated fluid retention. It also modulates serotonin receptor sensitivity and reduces prostaglandin-related cramping and mood lability.

Where to buy

Pharmacies and supplement retailers everywhere. Magnesium glycinate (by Thorne, Pure Encapsulations) is better tolerated than oxide. Avoid magnesium oxide if prone to loose stools.

Typical cost: $10-$25 per month

Safety notes

High doses (above 400 mg) can cause diarrhoea and stomach cramps. Reduce dose if this occurs. Consult your doctor if you have kidney disease, as magnesium is renally cleared.

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.

Clinical source

Walker et al., Magnesium supplementation alleviates premenstrual symptoms of fluid retention, J Womens Health, 1998

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.