New & Improved Standardized (Chasteberry) 0.5% Agnusides Herbal Supplement Kosher Parve Gluten Free Vegetarian Bluebonnet's Standardized Vitex Berry Extract Capsules provide a standardized extract of agnusides, the most researched active constituents found in vitex. A clean and gentle water-based extraction method is employed to capture and preserve vitex's most valuable components. Available in easy-to-swallow vegetable derived capsules for maximum assimilation/absorption and for a truly vegetarian/vegan formula.