1. Draw 1 mL bacteriostatic water with a sterile syringe.
2. Inject slowly down the vial wall; avoid foaming.
3. Gently swirl until dissolved (do not shake).
4. Label and refrigerate at 2 to 8 °C, protected from light. At 10 mg/mL, 1 unit = 0.01 mL » 100 mcg on a U-100 insulin syringe.

Oxytocin exerts its effects by binding to oxytocin receptors (OXTR), which are G-protein coupled receptors widely expressed in both central and peripheral tissues. In the brain, oxytocin acts as a neuromodulator: it is produced in the hypothalamus and released from the posterior pituitary, and also directly released within brain regions involved in emotion and social behavior. Activation of central OXTR influences neurotransmitter systems (enhancing prosocial signaling via dopamine and reducing stress responses via the hypothalamic-pituitary-adrenal axis). These actions underlie oxytocin’s observed effects on trust, empathy, and social bonding. Peripherally, oxytocin causes contraction of smooth muscles, including uterine muscle contraction during labor and milk ejection in lactation. It also can modulate pain perception and inflammation; studies show subcutaneous oxytocin produces local analgesia. Oxytocin does not significantly cross the blood-brain barrier from the bloodstream, so peripheral administration primarily targets peripheral OXTR, while intranasal administration is thought to better engage central receptors.

• Social and behavioral effects: oxytocin is associated with increased trust, social bonding, and reduced anxiety in social situations. Early studies show intranasal oxytocin can modestly improve social cognition or reduce anxiety in some populations.
• Psychiatric and neurological: being explored in PTSD, depression, and addiction. Its role in reducing the stress response and fear makes it a candidate for adjunctive treatment. Metabolic and weight management: a single intranasal oxytocin dose has been shown to reduce caloric intake and increase fat oxidation. Animal studies and small trials suggest chronic oxytocin treatment can lead to modest weight loss, improved insulin sensitivity, and reduced visceral fat.
• Analgesic and anti-inflammatory: a randomized trial found that a subcutaneous injection of oxytocin (4 mcg) significantly reduced ratings of heat pain intensity and unpleasantness on the treated arm.
• Reproductive health: as an established uterotonic, oxytocin (administered in much larger doses than research use) is routinely used to induce labor or reduce postpartum bleeding.
• Safety: placebo-like safety profile at doses roughly equivalent to 18 to 40 IU intranasally per administration (~30 to 67 mcg). An 8-week trial used 96 IU per day intranasally with no serious adverse events.