One of the numerous treatments suggested for premenstrual syndrome (PMS) is vitamin B₆. This vitamin, pyridoxine hydrochloride, is thought to relieve the depressive state and overall symptoms.

Wyatt and colleagues searched the medical literature and reviewed published and unpublished studies in any language that were conducted in a randomized, double-blind, placebo-controlled manner. Studies involving multivitamin supplements were included if the supplement contained at least 50 mg of vitamin B₆. The main outcome reviewed was a decrease in overall premenstrual symptoms, and a secondary outcome was a decrease in depressive premenstrual symptoms.

Ten studies with sample sizes ranging from 31 to 434 patients were included in the analysis. Dosages of vitamin B₆ ranged from 50 to 600 mg per day. The pooled results showed that vitamin B₆ relieved premenstrual symptoms. No dose response was found in nine of the trials.

The authors conclude that a meta-analysis of comparative studies demonstrates that vitamin B₆ relieves overall premenstrual and depressive premenstrual symptoms. Most studies were noted to be of poor quality.

In a commentary in the same journal, Macdougall notes the poor quality of the studies, caused by variations in the outcomes measures, the dosages of vitamin B₆ and whether the vitamin was used alone or in combination with other vitamins. She also notes that women with more severe symptoms, including those with premenstrual dysphoric disorder, usually do not respond to conservative interventions such as vitamin B₆ therapy. The lack of a dose response also puts further doubt on the utility of B₆ for treatment of premenstrual symptoms. Until better studies are conducted and because vitamin B₆ is readily available and inexpensive, and has minimal toxicity at dosages less than 200 mg, clinicians may recommend 100 mg daily as a conservative treatment option for pre-menstrual symptoms before giving medications that are more likely to be effective, such as selective serotonin reuptake inhibitors.