Jarrow Formulas® Milk Thistle Silymarin (Silybum marianum) 30:1 extract is standardized to contain 80% total Milk Thistle seed flavonoids, including the important Silymarin fractions isosilybinins A and B, silybinins A and B, silychristin and silydianin. This particular group of flavonoids, collectively known as Silymarin, supports liver function by helping to maintain protective glutathione levels.*