Which complementary therapies can help patients with PMS?

Evidence for magnesium is sparse
Two RCTs comparing magnesium with placebo had low precision because of small numbers and short treatment duration.^10,11 The first (N=28) demonstrated reduced total Moos Menstrual Distress Questionnaire scores.¹⁰ The second study reported a decrease in fluid retention symptoms by 2 points on an 80-point scale (P<.009) at 2 months, but no difference in total score.¹¹

A further study, begun as an open trial of magnesium infusion for premenstrual dysphoric disorder (N=6), found a dramatic reduction in mood symptom scores. After converting to a randomized, blinded design (N=10), no difference was found compared with placebo.¹²

St. John’s wort, evening primrose oil don’t work
One randomized, double-blind controlled trial (N=125) of 600 mg St. John’s wort vs placebo over 2 cycles of treatment found no significant changes in symptom score from baseline.¹³ Two double-blind crossover studies of 27 and 38 patients found that evening primrose oil had no effect on PMS symptoms.^14,15

Recommendations

The Premenstrual Syndrome Guidelines of the American College of Obstetricians and Gynecologists (ACOG) state that calcium and magnesium have been shown to be effective in small trials and must be validated in larger trials before a strong evidence-based recommendation can be made. ACOG’s guidelines also report minimal effectiveness with vitamin B6 and vitamin E.¹⁶