Licorice and liver function in patients with primary liver disease: A systematic review and meta-analysis of RCTs

Licorice (Glycyrrhiza spp.) has been a cornerstone of traditional Chinese and Japanese medicine. This systematic review and meta-analysis aimed to evaluate the efficacy of licorice formulations, alone or in combination with other herbs, on liver function enzymes in patients with primary liver disease. We systematically searched MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library up to April 2024. Randomized controlled trials (RCTs) comparing the effects of Glycyrrhiza spp. preparations versus placebo or standard of care controls were included. Standard Cochrane methods were used to extract data and appraise eligible studies. A total of 15 RCTs, involving 1367 participants, were included in the analysis. The studies varied widely in geographical location, duration, and licorice preparations used. Licorice significantly reduced alanine aminotransferase (ALT) by 15.63 U/L (95% CI: -25.08, -6.18; p = 0.001) and aspartate aminotransferase (AST) by 7.37 U/L (95% CI: -13.13, -1.61; p = 0.01) compared to control groups. Subgroup analyses revealed that purified glycyrrhizic acid compounds were particularly effective, showing greater reductions in ALT and AST without significant heterogeneity. Although licorice treatment did not significantly impact gamma-glutamyl transferase and total bilirubin (TBIL) levels overall, specific licorice-herb preparations did show a notable reduction in TBIL. The safety profile of licorice was consistent with known side effects, predominantly mild and related to its mineralocorticoid effects. Despite heterogeneity and potential language bias, the findings suggest that licorice can enhance liver function. Further studies should standardize licorice preparations and explore its role in multifaceted herbal formulations to better understand its hepatoprotective mechanisms.