Oxytocin
IU (intranasal) or pg/mL (plasma)
Neuropeptide sold as the trust hormone. The registered replication of the 2005 Nature RCT did not find the main effect.
Intranasal oxytocin was the 2010s shortcut from a nasal spray to social capital. Kosfeld et al. (2005) reported higher trust-game transfers after OT. Later reviews and a 2020 registered replication (Declerck et al., including original authors) did not recover the headline effect under the original minimal-social-contact condition. Treat OT as a molecule with a replication file, not as a management tool.
Also called OT, intranasal oxytocin.
Connected relationships
Randomized trial · High confidence
Oxytocin→Interpersonal trust
A rise in Oxytocin does not identify a change in Interpersonal trust.
Intranasal oxytocin does not raise trusting behavior: a 2026 registered report found no effect in 211 people, and a pooled equivalence test with the 2020 registered replication (532 people) put the leftover effect inside a minimal range.
Cases
Sources
- M. Kosfeld et al. (2005). Oxytocin increases trust in humans
- G. Nave et al. (2015). Does Oxytocin Increase Trust in Humans? A Critical Review of Research
- C. H. Declerck et al. (2020). A registered replication study on oxytocin and trust
- I Krug et al. (2024). The impact of oxytocin on emotion recognition and trust: Does disordered eating moderate these relationships?
- CF Kroll et al. (2026). Absence of a meaningful effect of intranasal oxytocin on trusting behavior: a registered report with pooled equivalence testing.