Studies in mice have shown that FGF-21 serves as a protective myokine in MASLD, enhancing the antioxidant response and providing protection against ferroptosis through mechanisms that activate the nuclear factor erythroid 2–related factor 2 (NRF2)/heme oxygenase-1 (HO-1)/glutathione peroxidase 4 (GPX4) pathway [104,105]. The gene discussed is GPX4; the disease is metabolic dysfunction-associated steatotic liver disease.