Pyridoxine (vitamin B6) and the premenstrual syndrome: a randomized crossover trial.

A randomized double-blind crossover trial was conducted to study the effects of pyridoxine (vitamin B6) at a dose of 50 mg per day on symptoms characteristic of the premenstrual syndrome. Sixty three women aged 18-49 years, identified by means of a general practice based survey of menstrual patterns in the community, entered the trial. All of the women had noticed moderate to severe premenstrual symptoms during the previous year. The women kept a daily menstrual diary which graded the severity of nine individual symptoms from zero to three. After completing a diary for an initial month the women were randomized to receive either drug or placebo for three months, after which the treatments were crossed over for a further three months. Thirty two women completed the full seven months of the study. In these women a significant beneficial effect (P less than 0.05) of pyridoxine was observed on emotional type symptoms (depression, irritability and tiredness). No significant effect was observed on premenstrual symptoms of any other type.