Herbal supplement. Highest purity. Purest source. Milk thistle extract. Twin Lab Silymarin (milk thistle extract) is of the highest quality and purity available. No tablet binders, coatings or colorings. Free of corn, soy, yeast, wheat, milk and egg products. Milk thistle extract, known scientifically as silymarin is a member of the compositae or daisy family. It is considered a flavanolignoid, which is a unique type of bioflavonoid. Twin Lab synergistically combines this unique bioflavonoid with citrus bioflavonoids in capsule form for greater nutritional benefits.