Four weeks of intranasal oxytocin in men with ASD produced endogenous oxytocin increases that persisted 4 weeks after stopping, with larger increases in those showing greater social improvement.
4 weeks post-treatmentendogenous oxytocin levels remained elevated after stopping intranasal OT administration
What the researchers found
Daily intranasal OT for 4 weeks increased endogenous salivary OT levels that persisted at 4-week follow-up. Increases were most pronounced in individuals with larger improvements in ASD social symptoms, suggesting a positive spiral of OT release.
Why it matters
If oxytocin treatment can kick-start a self-sustaining cycle of increased natural oxytocin production — especially linked to social improvement — it suggests treatment could have lasting benefits beyond the treatment period, addressing a key concern about peptide therapy dependency.
The numbers in context
4-week double-blind RCT; endogenous salivary OT levels changed with treatment vs placebo.
How the study worked
Double-blind, randomized, placebo-controlled study. 34 adult men with ASD received 4 weeks of daily intranasal OT (24 IU) or placebo. Salivary OT measured before, after, and at 4-week and 1-year follow-up. Between-subject design.
Who was studied
Adult men with autism spectrum disorder
What this study cannot tell us
Small sample size (34 participants). Only male adults with ASD studied. Saliva OT levels may not perfectly reflect brain OT activity. Mechanism of endogenous OT increase is inferred, not directly demonstrated.
How to read the evidence
Well-designed double-blind RCT with long-term follow-up. Small sample size limits power but the finding of persistent endogenous OT changes is novel and important.
When this study was published
Published in 2021. Longer-term oxytocin studies in ASD continue to explore the sustained effects concept.
The bigger picture
The concept of a 'positive spiral' — where exogenous oxytocin improves social behavior, which in turn triggers more natural oxytocin release — could fundamentally change how we think about peptide hormone therapy. Rather than lifelong supplementation, targeted treatment courses might produce self-sustaining benefits.
Questions still open
- Does the positive spiral of endogenous OT increase translate to sustained behavioral improvements?
- Would this effect be seen in women with ASD or in children?
- Could combining OT treatment with social skills training amplify the positive feedback loop?
Common questions
What is a positive spiral of oxytocin?
Does this mean oxytocin treatment for autism could be temporary rather than permanent?
Read the original research
Changes in endogenous oxytocin levels after intranasal oxytocin treatment in adult men with autism: An exploratory study with long-term follow-up.
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 43, 147-152
Citation
Alaerts, Kaat; Steyaert, Jean; Vanaudenaerde, Bart; Wenderoth, Nicole; Bernaerts, Sylvie. (2021). Changes in endogenous oxytocin levels after intranasal oxytocin treatment in adult men with autism: An exploratory study with long-term follow-up.. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 43, 147-152. https://doi.org/10.1016/j.euroneuro.2020.11.014