S-allylcysteine (SAC) is a water-soluble organosulfur compound derived from aged garlic extract (Allium sativum). Scientific interest in SAC stems from its antioxidant, anti-inflammatory, and hepatoprotective properties, which have been demonstrated in various preclinical studies. Specifically, SAC has been shown to protect the liver against damage induced by toxins such as carbon tetrachloride, acetaminophen, and alcohol in animal models. The hepatoprotective effects are attributed to SAC's ability to enhance the activity of endogenous antioxidant enzymes (such as superoxide dismutase, catalase, and glutathione peroxidase) and to reduce lipid peroxidation, thereby mitigating oxidative stress—a key factor in liver injury. Additionally, SAC may modulate inflammatory pathways and reduce hepatic fibrosis in experimental settings.

While these findings are promising, most of the evidence supporting SAC’s role in liver health comes from in vitro experiments and animal studies. There is a lack of robust clinical trials in humans directly assessing its efficacy in supporting the hepatic system. However, the mechanistic data and preclinical results provide a scientific rationale for its use as a supportive agent for liver health. Overall, the evidence can be considered moderate (3 out of 5), reflecting encouraging but not yet conclusive data for its role in hepatic support.