Metformin works primarily by decreasing glucose production in the liver, improving insulin sensitivity, and reducing glucose absorption from the intestines. It activates an enzyme called AMP-activated protein kinase (AMPK), which helps regulate glucose metabolism and energy balance, leading to better blood sugar control. Additionally, metformin inhibits certain mitochondrial enzymes, reducing glucose production and increasing glucose uptake by body tissues.
Mechanisms of Action
- Metformin decreases hepatic glucose production (gluconeogenesis) mainly by inhibiting mitochondrial enzymes, including complex I and complex IV activities, which reduces ATP production and activates AMPK, a key regulator of metabolism.
- AMPK activation leads to reduced glucose synthesis in the liver and increased glucose uptake and utilization by peripheral tissues like skeletal muscle.
- It also reduces the absorption of glucose from the intestines, contributing to lower blood sugar levels.
- Metformin increases insulin sensitivity, enhancing the body's response to insulin without increasing insulin secretion.
Additional Effects
- Metformin helps protect cells against various stresses through AMPK activation in multiple tissues.
- It has positive effects on cardiovascular health and may improve outcomes beyond diabetes control.
- It usually does not cause hypoglycemia and is associated with less weight gain compared to other diabetes treatments.
In summary, metformin is a multifaceted drug that improves blood glucose control by reducing liver glucose production, enhancing peripheral glucose uptake, and improving insulin sensitivity mainly through AMPK activation and mitochondrial enzyme inhibition.
