Silymarin has a historical application in treating several liver disorders (e.g., alcoholic liver disease, hepatotoxicity, cirrhosis, viral hepatitis). However, findings from clinical (human) studies are often conflicting.
Supplementation with silymarin may be beneficial for individuals affected by nonalcoholic fatty liver disease (NAFLD). One meta-analysis found that supplementation with silymarin reduced the levels of two liver enzyme biomarkers, alanine transaminase (ALT) and aspartame transaminase (AST), high levels of which can be indicative of liver damage.[1]
Additionally, positive preliminary results have been observed in individuals with liver cirrhosis and liver disease, showing a decrease in AST levels following supplementation with silymarin.[2]
Conversely, in individuals with chronic hepatitis C virus (HCV) infection, silymarin did not lead to a decrease in ALT levels compared to placebo, and it did not significantly impact HCV RNA levels (the concentration of HCV in the bloodstream). Although there was an improvement in some symptoms (mean physical functioning and bodily pain), these results suggest that silymarin may not be an effective treatment for chronic HCV infection.[3]