S-Allylmercaptocysteine (SAMC) is a bioactive organosulfur compound primarily derived from garlic (Allium sativum L.). It forms via the reaction between allicin and L-cysteine during garlic processing or metabolism. SAMC features a unique disulfide linkage connecting an allyl moiety to the thiol group of cysteine. Research indicates it exhibits antioxidant, anti-inflammatory, and potential anticancer activities by modulating pathways such as NF-κB, Nrf2, and apoptosis induction in tumor cells. It is more stable than allicin and has been investigated in preclinical models for hepatoprotective and chemopreventive effects. As a cysteine derivative, it participates in thiol-disulfide exchange reactions and may influence cellular redox balance.