Glutathione peroxidase 4 (GPX4) is an enzyme that plays a crucial role in cellular homeostasis and protection against oxidative stress. It is a lipid repair enzyme that functions to detoxify lipid hydroperoxides, which are harmful reactive oxygen species (ROS) generated during oxidative stress. It uses glutathione (GSH) as a cofactor to reduce lipid hydroperoxides to their corresponding alcohols, thereby preventing lipid peroxidation and subsequent cell damage. GPX4 plays a key role in preventing ferroptosis, a type of cell death characterized by iron-dependent accumulation of lipid ROS. Ferroptosis occurs when GPX4 activity is impaired, leading to uncontrolled lipid peroxidation and cell death. GPX4 has been also implicated in a variety of biological processes, including cancer development, neurodegeneration, and organ damage.