PeptideFederation

Neurohypophyseal hormone

Oxytocin

Also known as Pitocin, Syntocinon

Approved medicine

Summary

Oxytocin is a nine-amino-acid hormone made in the hypothalamus. Injected, it is an essential obstetric drug for labour and postpartum bleeding. Intranasal oxytocin became popular in social behaviour research after a 2005 study on trust, but larger and better-controlled trials have mostly failed to confirm the early findings.

Structure

  1. C1
  2. Y2
  3. I3
  4. Q4
  5. N5
  6. C6
  7. P7
  8. L8
  9. G9

HydrophobicGly / ProPolarBasic (+)Acidic (−)

C-terminally amidated, with a disulfide bridge between the two cysteines forming a six-residue ring.

How it works

Oxytocin acts on its own G-protein-coupled receptor in the uterus, breast and brain. How much intranasal oxytocin reaches the brain in people remains debated.

Research use cases

Areas where Oxytocin has been studied. Inclusion here does not mean it works for that purpose.

  • Labour induction and postpartum haemorrhage (approved)
  • Social cognition research
  • Autism spectrum disorder (tested)
  • Appetite and metabolism research

What the research found

Trust experiment

In an economic game, men given intranasal oxytocin transferred more money to a trustee, a widely cited 2005 result.1

Methodological critique

A 2016 analysis argued that many intranasal oxytocin studies were underpowered and that published effects were likely inflated.2

Autism trial

In 290 children and adolescents with autism, 24 weeks of intranasal oxytocin did not improve social or cognitive functioning compared with placebo.3

Safety and open questions

Injected oxytocin can cause uterine hyperstimulation and water intoxication at high doses. Intranasal use in trials was generally well tolerated.

Regulatory status

FDA-approved (Pitocin) by injection to induce or strengthen labour and control postpartum bleeding. Intranasal oxytocin is not FDA-approved.

Status was accurate when this page was last reviewed on October 26, 2026. Regulations change; check with the relevant authority before relying on it.

Oxytocin: common questions

Is oxytocin the “love hormone”?

That label oversimplifies it. Oxytocin influences social behaviour in context-dependent ways, and many early human findings have not replicated in larger trials.

Is Oxytocin approved for human use?

FDA-approved (Pitocin) by injection to induce or strengthen labour and control postpartum bleeding. Intranasal oxytocin is not FDA-approved.

References

  1. Kosfeld M, Heinrichs M, Zak PJ, Fischbacher U, Fehr E. (2005). Oxytocin increases trust in humans. Nature.
  2. Walum H, Waldman ID, Young LJ. (2016). Statistical and Methodological Considerations for the Interpretation of Intranasal Oxytocin Studies. Biological Psychiatry.
  3. Sikich L, Kolevzon A, King BH, et al. (2021). Intranasal Oxytocin in Children and Adolescents with Autism Spectrum Disorder. New England Journal of Medicine.

Links open a PubMed search for the exact title, or the original source where one is given.