Estera Phase I contains a blend of phytoestrogens, enzyme inducers, and other herbs for relief from PMS symptoms. Phytoestrogens are plant based compounds. They should be incorporated into a woman’ s diet from an early age for benefits throughout life. Estera Phase I also includes flaxseed lignans and indoles that work as enzyme inducers to help promote a healthy ratio of estrogen metabolites. Chasteberry and two sources of GLA provide relief from common, mild PMS symptoms like fatigue, mild mood swings, breast tenderness, and water retention.