Glutamate excitotoxicity has been observed in numerous diseases, such as ischemic stroke, traumatic brain injury (Zhou and Sheng, 2013), and Alzheimer’s disease (Mota et al., 2014), for which insulin resistance has been shown to be a risk factor or a symptom (Rundek et al., 2010; Talbot et al., 2012), and intranasal insulin has been shown to be a promising treatment (Craft et al., 2012; Lioutas and Novak, 2016; Brabazon et al., 2017). Here, INS is linked to Alzheimer disease.