Metformin primarily works by:

Choice A rationale Metformin, a biguanide, does not increase insulin secretion from the pancreas. Instead, it works independently of insulin secretion and is often used in patients with type 2 diabetes who still produce their own insulin, which is why it has a low risk of causing hypoglycemia. Choice B rationale Metformin's primary mechanism of action is to decrease the production of glucose by the liver, a process known as hepatic gluconeogenesis. By reducing this overproduction of glucose, it helps to lower elevated blood glucose levels in patients with type 2 diabetes. Choice C rationale Metformin does not increase carbohydrate absorption from the gastrointestinal tract. In fact, it has been shown to slightly decrease glucose absorption, which contributes to its overall glucose-lowering effect and may also be responsible for some of its gastrointestinal side effects. Choice D rationale While metformin does modestly increase insulin sensitivity in peripheral tissues, its primary and most significant effect is the reduction of hepatic glucose production. This is the main mechanism by which it lowers blood sugar, making it a cornerstone of type 2 diabetes treatment.