Biguanides are a type of oral medicine that is extensively used in the treatment of type 2 diabetes. Among these drugs, metformin is the most common and extensively used biguanide. It works by lowering glucose synthesis in the liver and increasing the body's sensitivity to insulin. This dual mechanism aids in blood sugar regulation. Metformin works by activating an enzyme called AMP-activated protein kinase (AMPK), which regulates cellular energy metabolism. Metformin lowers the generation of glucose in the liver by activating AMPK, which is a critical role in diabetes-related high blood sugar levels. It also improves insulin sensitivity and glucose utilization by the body's tissues by increasing the absorption of glucose by muscle cells. One of the most notable advantages of metformin is its minimal risk of inducing hypoglycemia (dangerously low blood sugar levels) when used alone. As a result, many healthcare providers choose it for the early management of type 2 diabetes. Metformin has sparked interest for its potential benefits beyond glycemic control, in addition to its principal role in diabetes management. Because of its effect on insulin levels and hormonal balance, metformin may have applications in other disorders such as polycystic ovarian syndrome (PCOS), according to some research. Despite its widespread usage and efficacy, metformin may cause negative effects in some people. The most typically reported side effects are gastrointestinal problems such as nausea, diarrhea, and abdominal discomfort. These, however, frequently fade with time as the body responds to the medicine. Furthermore, there have been worries regarding lactic acidosis, an uncommon but serious adverse effect related with metformin use. The development of lactic acid in the bloodstream causes symptoms such as weakness, trouble breathing, and abdominal discomfort. However, the risk of lactic acidosis with metformin is extremely low and occurs mostly in people who have underlying kidney or liver disorders. In conclusion, biguanides, particularly metformin, play an important role in the management of type 2 diabetes by decreasing blood sugar levels via several pathways. While they are generally well accepted, they may induce gastrointestinal adverse effects in some people, and those with certain medical conditions should exercise caution.