Oxytocin, the body's bonding and birth hormone, is a prescription medicine proven, by injection, to start labor and limit bleeding after birth; otherwise it is mostly taken nasally. It modestly cuts meal size, not body weight. Other effects are small, brief or inconsistent; longevity claims rest mainly on mouse studies. Nasal use looks reassuring short-term but lacks long-term data; injection, high or prolonged dosing and pregnancy carry the real hazards. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum sodium | 135–145 mmol/L | Safety check: low values stop or reduce use |
| Blood pressure and heart rate | Resting heart rate 60–100 beats per minute; blood pressure: no established target, track change from own baseline | Safety check: large falls or rises change route or dose |
| Pregnancy test (urine or blood) | No established target; a positive result stops use | Safety check: uterine stimulation |
| Lipid panel (LDL and HDL cholesterol) | No established target; track change from own baseline | Expected to change: conflicting LDL and HDL shifts in trials |
| Lean mass by DXA scan | No established target; track change from own baseline | Expected to change: lean-mass gain in a pilot trial |
Cadence: Baseline sodium, blood pressure, heart rate and, for women who could be pregnant, pregnancy test (lipids and body composition for metabolic or muscle goals); sodium at 2–4 weeks after starting or increasing dose frequency, then every 3–6 months; blood pressure and heart rate during the first doses and at each review; lipids and body composition at 8–12 weeks; pregnancy test after any missed period