FGF21, also known as Fibroblast Growth Factor 21, is a hormone-like protein that has garnered significant interest in the field of metabolic research due to its diverse effects on the body’s metabolism. It is primarily produced in the liver and other tissues like adipose tissue and the pancreas; FGF21 plays a crucial role in regulating glucose and lipid metabolism. It acts by sending signals to various organs to adapt to metabolic stress, like during fasting or a high-fat diet. FGF21 has been found to improve insulin sensitivity, stimulate glucose uptake in adipose tissues, and enhance lipid oxidation, making it a potential therapeutic target for conditions like diabetes, obesity, and non-alcoholic fatty liver disease. Additionally, it has been linked to regulating body weight and energy expenditure, further underscoring its potential in metabolic disease management. The study of FGF21 has opened new avenues for understanding and potentially treating metabolic disorders, although more research is needed to elucidate its mechanisms and therapeutic potential fully.