A dietary supplement to support immune system function. Maitake D-Fraction has been extensively researched, and is one of the most comprehensive immune support formulas available.* Our Maitake D-Fraction is a combination of Vitamin C, organic Maitake Mushroom Powder, and a trademarked brand of highly purified, standardized extract of Maitake mushroom called the PD-Fraction (professional strength) that yields 30% pure D-Fraction. FoodScience is proud to carry the D-Fraction from Maitake Products Inc. in our Maitake D-Fraction . This superior combination was formulated to help maintain optimal immune system function, improve antioxidant protection, and to support cholesterol, blood pressure, and cell growth within normal ranges. There is no other product on the market that is more pure or potent than Maitake D-Fraction.