Oxytocin

Why scientists study it

• It acts in the brain as a signal linked to social bonding, trust between people and close, friendly behavior in human and animal studies. Its effects on the uterus and breast have been known far longer.
• Scientists test it with nasal spray trials, brain scans and measures of the body’s own levels. They look at how the amygdala reacts to social and fear cues, at the stress hormone cortisol, and at empathy tasks.
• It is rare among research peptides because its lab-made form is also a prescription medicine, authorized by the MHRA for specific childbirth uses. That licensed use is fully separate from the unlicensed research-grade compound, and the two are not equal.

Three studies to know

Kosfeld et al., 2005 · Nature

Kosfeld and colleagues ran a widely cited trust game in people. Those given oxytocin by nasal spray trusted an unnamed partner more than those given placebo. Read the paper

Meyer-Lindenberg et al., 2011 · Nature Reviews Neuroscience

Meyer-Lindenberg and colleagues wrote a thorough review that places oxytocin and vasopressin in the field of social brain peptides. It pulls together what was known by then about how they work and what human studies mean for medicine. Read the paper

Kirsch et al., 2005 · The Journal of Neuroscience

Kirsch and colleagues scanned the brains of healthy adults. After oxytocin by nasal spray, the amygdala reacted less to fearful and threatening social images. Read the paper

Safety and legal status

• Lab-made oxytocin is a prescription-only medicine (Syntocinon is one brand), authorized by the MHRA for specific licensed childbirth uses. The research-grade compound is a separate, unlicensed product.
• The World Anti-Doping Agency does not currently list it as a banned substance.
• For laboratory research use only. It is not for use in people.