PMS and PMDD: what actually works

A great many supplements are marketed for premenstrual symptoms. In a systematic review of herbs, vitamins and minerals for PMS, only calcium had good-quality evidence supporting its use — 1,200 mg/day, associated with roughly a 48% reduction in total PMS symptoms and 30% in PMDD symptoms.

Vitamin B6 has supportive but lower-quality evidence: across 9 trials and 940 women, doses up to 100 mg/day improved overall premenstrual symptoms (OR 2.32) and depressive symptoms (OR 1.69), though the authors stressed most trials were poor quality. Important: Filia defaults B6 to 10–25 mg because sustained high-dose B6 can cause nerve damage. PMS trials used higher doses cyclically — luteal phase only — which is a very different cumulative exposure from taking 100 mg every day year-round. If you use a higher dose, use it for part of the cycle and discuss it with your provider.

Vitex has been tested in multiple RCTs for PMS with consistent benefit, and in one small head-to-head trial in diagnosed PMDD it matched fluoxetine for physical symptoms while fluoxetine did better on psychological ones.

Honest framing: none of these match SSRIs or hormonal treatment for moderate-to-severe PMDD. For mild symptoms, or alongside medication, they are reasonable. For severe PMDD, supplements alone are unlikely to be sufficient — and that is worth knowing rather than discovering slowly.