Since the HPT axis plays a fundamental role in metabolic pathways involving lipids and carbohydrates, the existence of a link between TH dysfunction and liver diseases has been explored over the years; in particular, the relationship between non-alcoholic fatty liver disease (NAFLD), also known as metabolic dysfunction-associated steatotic liver disease (MASLD), and hypothyroidism has recently attracted growing interest in the scientific community. The gene discussed is TH; the disease is metabolic dysfunction-associated steatotic liver disease.