Insulin nasal spray may slow Alzheimer's. Insulin Nasal Spray May Slow Alzheimer’s, Inhaled insulin via a nasal spray may slow the deterioration of cognitive function in people with Alzheimer’s disease and amnestic mild cognitive impairment, a condition thought to precede Alzheimer’s disease, according to the results of a pilot study published online for the first time in the journal Archives of Neurology on Monday.