Claimed effect · Setmelanotide

Does Setmelanotide help with weight loss in Bardet-Biedl syndrome?

B
Grade B — probable, not settled1 phase 3 with 14-wk placebo-controlled period (n=38) · effect size: moderate
Short answerProbable, not settled. Human data exist (1 phase 3 with 14-wk placebo-controlled period (n=38)) and mostly agree, showing a moderate effect — but too few, too small, or not yet peer-reviewed for a firm answer. The basis of the 2022 approval extension; the only setmelanotide trial with a randomised placebo period.

What the studies show

The basis of the 2022 approval extension; the only setmelanotide trial with a randomised placebo period.

Human trials exist and mostly agree, but there are too few of them, they are too small, or one big one is still reading out. Expect the grade to move.

  1. 1

In context

Setmelanotide is a cyclic analogue of α-MSH that activates the MC4 receptor, the brain's main satiety switch. In people whose obesity is caused by rare mutations upstream of that receptor — POMC, PCSK1 or LEPR deficiency, or Bardet-Biedl syndrome — it restores the signal: 80% of POMC-deficient and 45% of LEPR-deficient patients lost at least a tenth of their body weight in a year, with hunger scores falling by a quarter to a half. Those trials had ten and eleven participants. In obesity that follows damage to the hypothalamus, a 120-person randomised trial found BMI fell 16.5% against a 3.3% rise on placebo; Canada approved that use in September 2026. It has no role in common obesity.

Setmelanotide is approved (rx) — rare genetic obesity; hypothalamic obesity in canada. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is Setmelanotide proven to help with weight loss in Bardet-Biedl syndrome?
Not yet settled. 1 phase 3 with 14-wk placebo-controlled period (n=38) — LYO grades it B, meaning probable but liable to change as trials read out.
What studies are behind the grade?
The basis of the 2022 approval extension; the only setmelanotide trial with a randomised placebo period.
Is Setmelanotide approved for this?
Setmelanotide is an approved medicine (Approved (Rx) — rare genetic obesity; hypothalamic obesity in Canada); whether this particular outcome is a licensed indication is stated on the compound page's regulation section.

Other outcomes for Setmelanotide

Written and maintained by LYO Research — how pages are written and checked. Reviewed 7 October 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →