Neuroendocrine

Oxytocin

Also: Pitocin · Syntocinon

Nine-amino-acid hypothalamic hormone that drives labor contractions and milk let-down; the nasal spray is studied for social behavior.

Discussion

Overview

What it is

Oxytocin is made in the hypothalamus and released from the posterior pituitary. The IV form (Pitocin) is a standard obstetric drug. Intranasal oxytocin is a psychiatry research tool with mixed results, and a large 2021 trial found no benefit for autism.

Common forms

IV or IM injection (obstetrics, prescription)Intranasal spray (research or compounded)

Mechanism

How it works

Binds the oxytocin receptor, a Gq-coupled receptor in uterine muscle, breast tissue and brain areas such as the amygdala, raising intracellular calcium.

Oxytocin receptor → PLC → calcium releaseUterine smooth-muscle contractionMilk-ejection reflex

↑Uterine contractions

↑Milk let-down

~Social processing (intranasal, inconsistent)

Hormonal impact

~Prolactin

↓Cortisol (stress response)

Evidence

What the research supports

Induces or strengthens labor contractions (IV, prescription)strong

Prevents and treats postpartum hemorrhagestrong

Intranasal effects on social behavior; large autism trial was negativelimited

Safety

Side effects & interactions

Side effects

Nasal irritation (intranasal)
Headache
Nausea
Uterine overstimulation (IV) serious
Low blood sodium from water retention at high IV doses serious

Medications

Prostaglandins / other uterotonicsmoderateAdditive uterine stimulation in obstetric use.

Stacking

Combines with

Pairs well

Nothing specific.

Avoid combining

Pregnancy outside medical careCan trigger uterine contractions.

Community

Discussion

Experiences from people who have tried Oxytocin. Anecdotes are not medical advice.

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