By goal
Evidence-Backed Supplements for PMS & Period Pain
Premenstrual syndrome (PMS) and painful periods (dysmenorrhoea) prompt many people to look for relief beyond painkillers, hoping to ease cramps, bloating, breast tenderness, and mood swings. The supplement evidence here is genuinely uneven. The strongest, most consistent human data sit with a few well-studied nutrients: omega-3 (EPA/DHA), vitamin D3, and iron, the last of which matters mainly when blood tests confirm a deficiency rather than as a routine add-on. Saffron, magnesium, and inositol (myo-inositol) carry moderate, promising but smaller-trial support, with inositol studied more for PCOS-related cycles than PMS mood directly. Others are popular but poorly backed: evening primrose oil (GLA) has not held up in higher-quality trials, and dong quai rests largely on tradition rather than robust evidence. We grade each option against published studies so you can see what is solid and what is not. This page is educational, not medical advice; talk to your doctor or pharmacist before starting any supplement.
| Supplement | Evidence for this goal | Typical dose | Key caution | Studies |
|---|---|---|---|---|
| Iron | Strong | Treatment ~40–60 mg elemental; alternate-day dosing may absorb better.… | Constipation, nausea and dark stools are common. | 17 |
| Omega-3 (EPA/DHA) | Strong | 1–2 g combined EPA+DHA/day; up to 4 g (Rx) for high triglycerides. | Safe at typical doses. | 20 |
| Vitamin D3 | Strong | 1,000–2,000 IU/day maintenance; higher to correct deficiency under test… | Tolerable upper limit ~4,000 IU/day for most adults; toxicity (hypercalcemia) occurs with c… | 16 |
| Evening Primrose Oil (GLA) | Moderate for this goal | Commonly 4–6 g oil/day (~320–480 mg GLA). | Generally well tolerated; mild, temporary GI upset is most common. | 16 |
| Inositol (Myo-Inositol) | Moderate | PCOS: typically 2 g myo-inositol twice daily (4 g/day), often with 400… | Generally well tolerated; the most common side effects are mild, dose-related gastrointesti… | 14 |
| Magnesium | Moderate | 200–400 mg elemental/day. Glycinate & citrate absorb best; oxide is poo… | Safe. | 20 |
| Saffron | Moderate | 30 mg/day standardized extract. | Safe at supplement doses. | 20 |
| Dong Quai | Mixed | Commonly 3–15 g in decoction or formula; rarely used alone in TCM. | May increase bleeding (avoid with anticoagulants) and photosensitivity. | 17 |