Impact of Silymarin Supplements on Liver Enzyme Levels: A Systematic Review

Silymarin, extracted from milk thistle (Silybum marianum), is esteemed for its antioxidative, anti-inflammatory, and antifibrotic properties, notably within liver-related contexts. Nevertheless, a comprehensive grasp of its effects on liver enzymes remains elusive. This systematic review aims to scrutinize the influence of silymarin supplements on liver enzyme levels, elucidating its potential for hepatoprotection. Following PRISMA 2020 guidelines, we systematically reviewed pertinent studies in PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online). Our inclusion criteria comprised randomized clinical trials (RCTs) published between 1992 and 2023, accessible in English, with a primary focus on liver enzyme levels. Non-original research, ambiguously defined studies, and those lacking essential data were excluded. Of the 1,707 initially identified articles, 29 RCTs met the inclusion criteria, encompassing 3,846 participants with diverse underlying conditions. Silymarin dosages ranged from 140 mg to 420 mg, administered for various durations. Results revealed that 65.5% of the studies reported reduced liver enzyme levels, 20.7% exhibited no significant change, and 13.8% observed elevated liver enzymes. The systematic review implies a potential advantageous influence of silymarin on liver enzyme levels, indicating its hepatoprotective potential. Nevertheless, outcome disparities may stem from comorbidities, suboptimal doses, and underlying diseases. Notably, silymarin's impact on liver enzymes could be context-dependent, with varying responses among different conditions, with the decrease of liver enzyme levels in patients with non-alcoholic fatty liver disease. Silymarin supplements exhibit potential for hepatoprotection by ameliorating liver enzyme levels across diverse conditions. Further research should ascertain optimal dosages and contexts, accounting for individual patient characteristics and underlying diseases.