Therefore, the following subsections will provide an in-depth analysis of alterations in the main antioxidant enzymes, including SODs, CAT, GPxs, GSTs, GR, and NQO1, as well as in the non-enzymatic antioxidant GSH observed in MASLD patients as well as in various MASLD/MASH experimental models. The gene discussed is GSR; the disease is metabolic dysfunction-associated steatotic liver disease.