How Does Metformin Actually Work in the Body?

Metformin is a widely prescribed oral antidiabetic drug that has been used for over 60 years to treat type 2 diabetes. It's also prescribed for polycystic ovary syndrome (PCOS) and is being studied for its potential benefits in weight loss and non-alcoholic fatty liver disease. Despite its long history of use, many people are unclear about how metformin actually works in the body. In this article, we'll break down the complex science behind metformin's effects on glucose metabolism.

Metformin is a biguanide, a class of medications that are known to decrease glucose production in the liver. When you eat, your body breaks down carbohydrates into glucose, which is then absorbed into the bloodstream. Normally, this triggers the release of insulin, a hormone produced by the pancreas that helps glucose enter your cells. However, in people with type 2 diabetes, the body either resists the effects of insulin or doesn't produce enough of it. Metformin works by reducing the amount of glucose produced by the liver, which in turn decreases the amount of glucose in the bloodstream.

How Metformin Reduces Glucose Production

When you eat, your liver responds by breaking down stored glycogen (a complex carbohydrate) into glucose and releasing it into the bloodstream. Normally, this process is tightly regulated by hormones such as insulin and glucagon. However, in people with type 2 diabetes, the liver continues to produce glucose even when blood glucose levels are high, a process known as "glucose overproduction." Metformin works by inhibiting this process, reducing the amount of glucose produced by the liver and decreasing the amount of glucose in the bloodstream.

The Role of AMPK in Metformin's Action

Metformin's effects on glucose metabolism are thought to be mediated by the activation of an enzyme called AMP-activated protein kinase (AMPK). AMPK is a key regulator of energy balance in the cell, and when activated, it inhibits the production of glucose in the liver and increases the uptake of glucose by muscles. Metformin is thought to activate AMPK by increasing the production of a molecule called AMP (adenosine monophosphate), which in turn activates AMPK. This activation of AMPK is thought to be the key mechanism by which metformin reduces glucose production in the liver.

The Benefits of Metformin

Metformin has several benefits that make it a popular choice for treating type 2 diabetes. It's been shown to:

• Reduce glucose production in the liver
• Improve insulin sensitivity
• Decrease the risk of cardiovascular disease
• Have weight loss effects
• Have potential benefits in PCOS and non-alcoholic fatty liver disease

Potential Side Effects

While metformin is generally well-tolerated, it can have some side effects, including:

• Gastrointestinal symptoms such as diarrhea, nausea, and abdominal pain
• Vitamin B12 deficiency
• Lactic acidosis (a rare but serious side effect)

Conclusion

Metformin is a powerful medication that has been used for decades to treat type 2 diabetes. Its effects on glucose metabolism are complex, but it's thought to work by reducing glucose production in the liver and increasing insulin sensitivity. By understanding how metformin works, we can better appreciate its benefits and potential side effects. If you have type 2 diabetes or are at risk of developing it, talk to your doctor about whether metformin is right for you.