Intranasal insulin administration is a novel approach to the treatment of diabetic polyneuropathy (DPN) based on robust basic science research. Intranasal insulin is currently being studied in other conditions and has completed Phase II in subjects with cognitive impairment and mild Alzheimer's disease. Intranasal administration of insulin results in increased penetration into the cerebrospinal fluid and the peripheral nervous system while avoiding systemic absorption. Lack of systemic absorption results in maintenance of normal blood glucose levels in normal healthy subjects.