Hormonal Support Herbal Supplement Supports Hormone Production and Balance Helps Ease Women's Monthly Discomfort Full Spectrum® Whole Fruit Formula Science-Backed Quality Since 1969 Vegan Non-GMO Gluten Free Dairy Free Halal Swanson Full Spectrum® Chasteberry Fruit, also known as Vitex agnus-castus, has a long history of use by women during their periods. Studies suggest that it has a progesterone-like effect, which may account for its use in the support of women's health. Because of this activity, chasteberry has been recommended for a variety of issues common to PMS including mood, body tenderness and water balance. Chasteberry Fruit, also known as Vitex agnus- castus, has a long history of use by women during their periods.