Claimed effect · Oxytocin (intranasal)

Does Oxytocin (intranasal) help with weight loss in obesity?

C
Grade C — weak human evidence1 RCT (n=61) · effect size: not measurable
Short answerWeak human evidence. 1 RCT (n=61): enough to be interesting, not enough to count on. Where an effect is seen it is no measurable effect, or none yet shown. Eight weeks of intranasal oxytocin four times daily produced no weight change versus placebo, though it modestly reduced intake at a single test meal.

What the studies show

Eight weeks of intranasal oxytocin four times daily produced no weight change versus placebo, though it modestly reduced intake at a single test meal.

“There was no difference in body weight change from baseline to week 8 between oxytocin and placebo groups (0.20 vs. 0.26 kg; P=0.934).”

Verbatim, from the abstractPlessow F, et al. Intranasal oxytocin for obesity. NEJM Evidence, 2024;3:EVIDoa2300349

A few small or poorly-controlled human studies. Enough to be interesting; not enough to count on. Most of what gets called “clinically proven” online lives here.

  1. 1
    Plessow F, et al. Intranasal oxytocin for obesity.NEJM Evidence, 2024;3:EVIDoa230034961 adults, 8 weeks; no weight change, reduced single-meal intake.

In context

Oxytocin is a natural nine-amino-acid hormone, licensed for decades as an injection to induce labour and control bleeding. The compound sold and discussed in the peptide world is intranasal oxytocin, promoted for bonding, appetite and social behaviour. Here the evidence is largely negative: the largest randomised trial in autism found no benefit, and a randomised obesity trial found no weight loss. It is well tolerated, but the popular claims rest on small early studies that the big trials did not confirm.

Oxytocin (intranasal) is approved (rx) as injection; intranasal use unlicensed. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is Oxytocin (intranasal) proven to help with weight loss in obesity?
No. The human evidence is weak (1 RCT (n=61)); LYO grades it C.
What studies are behind the grade?
Eight weeks of intranasal oxytocin four times daily produced no weight change versus placebo, though it modestly reduced intake at a single test meal.
Is Oxytocin (intranasal) approved for this?
Oxytocin (intranasal) is an approved medicine (Approved (Rx) as injection; intranasal use unlicensed); whether this particular outcome is a licensed indication is stated on the compound page's regulation section.

Other outcomes for Oxytocin (intranasal)

Written and maintained by LYO Research — how pages are written and checked. Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →