What is the active ingredient in Actos?

Pioglitazone is the active ingredient in Actos, which is a medication commonly prescribed for managing type 2 diabetes. It belongs to a class of drugs known as thiazolidinediones (TZDs) and works by improving insulin sensitivity, thus helping the body use glucose more effectively. By enhancing the action of insulin, it can help lower blood sugar levels and improve metabolic control in individuals with diabetes.

Other drug options listed have distinct uses: Metformin, for instance, is another oral diabetes medication primarily used to decrease glucose production in the liver and improve insulin sensitivity but is not the active ingredient in Actos. Repaglinide and Nateglinide are also medications for type 2 diabetes but belong to a different class called meglitinides, which work by stimulating insulin release from the pancreas. These differences reinforce that pioglitazone is specifically the active substance in Actos, making it the correct answer in this context.