# Does magnesium help PMS and period cramps?

Source: https://www.healthnews24.co.za/answers/magnesium-for-pms-and-period-cramps/
Publisher: Healthnews24 (South Africa's supplement answer desk)
Updated: 2026-10-27

> Magnesium may modestly ease PMS symptoms and period cramps for some women, but the evidence is low to moderate, based on small trials of mixed quality. Supplemental doses of 100–350 mg elemental magnesium a day are typical; EFSA's upper level for supplements is 250 mg. Severe or worsening period pain needs a doctor, not a supplement.

Key facts:
- Evidence for magnesium in PMS and period pain is low to moderate: small trials of mixed quality.
- Supplemental magnesium is typically 100–350 mg elemental a day; the EFSA upper level for supplements is 250 mg a day.
- The Real Thing Tri-Mag works out at about R2.64 per 100 mg elemental magnesium (R285 for 90 capsules, Faithful to Nature, October 2026).
- The main side effect is diarrhoea; magnesium supplements are unsuitable in kidney failure.
- Severe, worsening or new period pain should be assessed by a doctor.

## Does magnesium help PMS and period cramps?

Possibly, a little. Magnesium is involved in muscle relaxation and nerve signalling, and some small trials report fewer cramps or milder mood symptoms with supplements. An older Cochrane review of dietary and herbal treatments for period pain found some promising results for magnesium and a few other options, but they rested on few, small studies, and that review is now old. Our evidence rating is **low to moderate**: worth a trial for some women, not a proven fix.

## What dose is used?

Supplements typically provide 100–350 mg of **elemental** magnesium a day. The EFSA tolerable upper level for supplemental (not food) magnesium is 250 mg a day for adults, set because larger amounts cause diarrhoea. Always read the elemental figure on the label, not the compound weight.

| Form | Notes |
|---|---|
| Glycinate / bisglycinate | well absorbed, gentler on the gut |
| Citrate | well absorbed, can loosen stools |
| Oxide | high elemental content, lower absorption |
| Sulphate | cheapest per mg, laxative effect at higher doses |

## What does it cost in South Africa?

Cost per 100 mg of elemental magnesium, from label amounts (October 2026, our calculation):

- **The Real Thing Tri-Mag** (about 120 mg per capsule, 2 a day): about R2.64 per 100 mg at R285 for 90 capsules, Faithful to Nature. It also contains vitamin D3, so count that toward your total.
- **Flora Force Magnesium Glycinate:** about R2.82 per 100 mg at R169 for 60 (we read 100 mg per capsule from the label wording).
- **Dis-Chem Gold Magnesium Chelate** (99 mg per tablet): about R3.37 per 100 mg at R300 for 90, Dis-Chem Living Fit.

See our full [magnesium comparison](/best/best-magnesium-south-africa/) and [how much magnesium per day](/answers/how-much-magnesium-per-day/).

## How should you take it?

Start low, around 100–200 mg in the evening with food, and give it two to three menstrual cycles before judging. Stop if you get diarrhoea. Take it a few hours apart from tetracycline or quinolone antibiotics and bisphosphonates. People with kidney disease should avoid magnesium supplements unless prescribed, because they cannot clear the excess.

## What else has better support for period pain?

Heat packs, regular exercise and, where suitable, anti-inflammatory pain relief recommended by your pharmacist or doctor all have stronger evidence. Magnesium is a supporting option. For mood-related PMS symptoms, sleep, exercise and a clinician's review of other causes come first.

## When should you see a doctor?

See a doctor if pain stops you working or studying, is getting worse, comes with very heavy bleeding, or is new after age 25. Severe period pain can have causes such as endometriosis that a supplement will not address. Do not use magnesium to self-treat a diagnosed condition. Teenagers with painful periods, and anyone who is pregnant or might be, should ask a doctor or pharmacist before taking supplements. If you take a hormonal contraceptive or other medicine, ask a pharmacist; see [do supplements interact with hormonal contraceptives](/answers/do-supplements-interact-with-the-pill/). For the sleep angle, read [does magnesium help sleep and cramps](/answers/does-magnesium-help-sleep-and-cramps/).

## Products mentioned

| Product | Size | Price (source, date) | Servings | R per serving | Sweeteners |
|---|---|---|---|---|---|
| The Real Thing Tri-Mag 90 capsules | 90 capsules | R285 (Faithful to Nature, 2026-10) | 45 | R6.33 | not stated |
| Flora Force Magnesium Glycinate 60 capsules | 60 capsules | R169 (Faithful to Nature, 2026-10) | 30 | R5.63 | not stated |
| Dis-Chem Gold Magnesium Chelate 90 coated tablets | 90 tablets | R300 (Dis-Chem Living Fit, 2026-10) | 60 | R5.00 | not stated |

## Sources

- [Proctor ML, Murphy PA. Herbal and dietary therapies for primary and secondary dysmenorrhoea (Cochrane Database Syst Rev)](https://pubmed.ncbi.nlm.nih.gov/11687013/)
- [EFSA: Overview of tolerable upper intake levels (summary report, 2024)](https://www.efsa.europa.eu/sites/default/files/2024-05/ul-summary-report.pdf)
- [Australian Institute of Sport Supplement Framework: Group C](https://www.ausport.gov.au/ais/nutrition/supplements/group_c)