ill help,
when you STOP taking these supplements your body is MORE sensitive to insulin, there will be no rebound or insulin resistance following these supplements.
Ingredients in most (not all) GDAs take a lot of pressure off the pancrease, and reduce the amount of insulin needed to lower your blood sugar for the same amount of carbs. Ingredients like Gymnema as shown in studies can regenerate beta cell function and can improve their insulin sensitivity even after stopping the supplements. Studies vith vanadyl show that insulin sensitivity remains the same for weeks after stopping.
all in all once stopping your body is able to use less insulin, and function more efficiently at carbohydrate disposal, and glucose clearing from the blood.