Milk Thistle (Silybum marianum) for the Treatment of Alcoholic and Non-Alcoholic Fatty Liver Disease: A Systematic Review

Abstract

Introduction: Milk thistle, and its active component silymarin, is a widely used herbal product for liver disorders due to its antioxidant properties. This review systematically evaluates its efficacy in patients with alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD).

Methods: A search of MEDLINE and Scopus was performed for RCTs up to December 2019. We included trials that compared milk thistle to placebo or no intervention in patients with ALD or NAFLD, assessing outcomes such as liver enzymes (ALT, AST), liver histology, and mortality.

Results: We identified 22 RCTs. In patients with ALD, milk thistle did not show a significant effect on mortality or histological progression of the disease. For NAFLD, several studies showed a significant reduction in ALT and AST levels compared to placebo, but improvements in histology (steatosis, inflammation) were inconsistent.

Discussion: The evidence for the clinical benefit of milk thistle in liver diseases is weak. While it appears to improve liver enzyme profiles in NAFLD patients, its impact on long-term clinical outcomes like fibrosis or mortality remains unproven. The bioavailability of different formulations is a key limitation.

Conclusion: Pre-2020 evidence does not support the routine use of milk thistle for patients with alcoholic or non-alcoholic fatty liver disease, although it appears to be safe.