A number of supplements, such as myo-inositol, calcium, vitamin E, vitamin D, St. John's Wort, saffron, magnesium, fish oil, curcumin, vitamin B6, vitex agnus-castus (chaste tree), and evening primrose oil, have been studied for premenstrual symptoms.[1][2] Most are only effective for mild to moderate symptoms, when used in combination with other therapies, or to correct nutritional deficiencies.[3] In fact, compared to PMS, there are few trials specific to supplements for PMDD. Chaste tree is perhaps the most well-studied, and although some trials find that it reduces PMDD symptoms, the quality of available evidence is low[4], and it may not be as effective for psychological symptoms as antidepressants.[5]