Intranasal insulin improves memory in humans: superiority of insulin aspart

Neuropsychopharmacology. 2007 Jan;32(1):239-43. doi: 10.1038/sj.npp.1301193. Epub 2006 Aug 16.


There is compelling evidence that intranasal administration of regular human insulin (RH-I) improves memory in humans. Owing to the reduced tendency of its molecules to form hexamers, the rapid-acting insulin analog insulin aspart (ASP-I) is more rapidly absorbed than RH-I after subcutaneous administration. Since after intranasal insulin administration, ASP-I may also be expected to access the brain, we examined whether intranasal ASP-I has stronger beneficial effects on declarative memory than RH-I in humans. Acute (40 IU) and long-term (4 x 40 IU/day over 8 weeks) effects of intranasally administered ASP-I, RH-I, and placebo on declarative memory (word lists) were assessed in 36 healthy men in a between-subject design. Plasma insulin and glucose levels were not affected. After 8 weeks of treatment, however, word list recall was improved compared to placebo in both the ASP-I (p<0.01) and the RH-I groups (p<0.05). ASP-I-treated subjects performed even better than those of the RH-I-treated group (p<0.05). Our results indicate that insulin-induced memory improvement can be enhanced by using ASP-I. This finding may be especially relevant for a potential clinical administration of intranasal insulin in the treatment of memory disorders like Alzheimer's disease.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal*
  • Adolescent
  • Adult
  • Analysis of Variance
  • Blood Glucose / drug effects
  • Double-Blind Method
  • Drug Administration Schedule
  • Humans
  • Hypoglycemic Agents / administration & dosage*
  • Insulin / administration & dosage*
  • Insulin / analogs & derivatives*
  • Insulin / blood
  • Insulin Aspart
  • Male
  • Memory / drug effects*
  • Memory / physiology
  • Neuropsychological Tests


  • Blood Glucose
  • Hypoglycemic Agents
  • Insulin
  • Insulin Aspart