Non-invasive delivery of insulin has attracted much attention in recent years. In this paper, we investigated the possibilities of insulin delivery via several non-invasive routes such as pulmonary, oral and the buccal ways.Pulmonary delivery of insulinWe Non-invasive delivery of insulin has attracted much attention in recent years. In this paper, we investigated the possibilities of insulin delivery via several non-invasive ways such as pulmonary, oral and the buccal ways.