Type 1 has been reversed through pancreas and islet transplants, recently in at least one individual by stem cell transplants, now he makes his own insulin.

For some type 2 individuals diagnosed early enough, blood sugar can be managed through diet and exercise, and insulin response can be normalized back to typical levels. This seems to work best when caught early, and when the person has the ability to make long lasting lifestyle changes. And the risk of relapse seems to remain much higher than in the general population.