For each selected participant (n=27), a baseline olfactory measurement was performed with Sniffin Sticks® (12 items) and a capillary glucose measurement was obtained with Dextrostix® NF before and after the intervention, in order to guarantee patient safety and reduce the risk of hypoglycemia. The initial and final measurements were divided into three subsections with a different number of correct answers for each section Subsequently, Gelfoam® cottonoids soaked in 40 IU of NPH insulin were placed on the nasal roof (between the nasal septum and the middle meatus) of each nostril. These remained in place for 15 minutes and were later removed. This procedure was performed in three visits one week apart. During the fourth and last visit (one week after the previous visit), olfaction was reevaluated using the measures previously described.

Gelfoam® cottonoids soaked in 40 IU of NPH insulin were placed on the nasal roof (between the nasal septum and the middle meatus) of each nostril. These remained in place for 15 minutes and were later removed. This procedure was performed in three visits one week apart. During the fourth and last visit (one week after the previous visit), olfaction was reevaluated using the measures previously described.