Nature’s Way Milk Thistle Standardized Description: Premium Extract 80% Silymarin. Milk Thistle Extract is standardized to 80% silymarin, the key constituent that exerts a protective effect against substances potentially harmful to the liver. Health and longevity through the healing power of nature – that is what it means to Trust the Leaf. Disclaimer These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.