What is the primary mechanism by which metformin exerts its therapeutic effect in the treatment of type 2 diabetes?

A Stimulation of insulin release from pancreatic beta cells
B Inhibition of glucose production in the liver ✓
C Enhancement of glucose uptake in skeletal muscle
D Inhibition of lipolysis in adipose tissue

Explanation

Metformin primarily works by inhibiting gluconeogenesis in the liver, which reduces hepatic glucose production and lowers blood glucose levels.

Source

ADA Standards of Medical Care in Diabetes
Metabolic and Nutritional Disorders Diabetes Management Pharmacotherapy of Type 2 Diabetes Medium MEDICAL Confidence: high