Resmetirom: A Breakthrough in the Treatment of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD).

Background and Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD), previously referred to as non-alcoholic fatty liver disease (NAFLD), has become the most prevalent chronic liver disease worldwide. Its increasing incidence is closely linked with rising rates of obesity, Type 2 diabetes mellitus (T2DM), and metabolic syndrome. MASLD includes a spectrum of liver pathologies such as fibrosis, cirrhosis, and metabolic dysfunction-associated steatohepatitis (MASH). This review explores diagnostic advancements and therapeutic developments, focusing on Resmetirom, a selective thyroid hormone receptor-beta (THR-β) agonist, as a novel pharmacologic intervention. Methods: The review draws upon current literature, clinical guidelines, and data from pivotal randomized controlled trials to evaluate the diagnostic criteria, non-invasive assessment tools, lifestyle recommendations, and emerging pharmacotherapy for MASLD and MASH, focusing on Resmetirom. Results: Resmetirom has demonstrated significant efficacy in reducing hepatic fat content and improving markers of liver fibrosis in patients with noncirrhotic MASH and fibrosis stages F2-F3. Clinical trials showed improved liver histology, lipid profiles, and MASH resolution without fibrosis progression. Despite its promising profile, gastrointestinal side effects and gallstone-related complications have been observed. Long-term safety and outcomes related to cirrhosis or hepatocellular carcinoma prevention remain under investigation. Conclusion: MASLD is a significant public health concern driven by metabolic dysfunction. While lifestyle changes remain central to management, Resmetirom offers a promising pharmacological option for patients with moderate to advanced MASH. Further long-term studies are needed to fully establish its safety, effectiveness, and role in preventing advanced liver disease.