What it means
Setmelanotide switches on the MC4R receptor in the brain, part of a pathway that tells the body it has enough energy stored. In some rare conditions this pathway is broken upstream, causing intense hunger from early childhood.
The FDA first approved it as Imcivree in 2020 for obesity caused by confirmed POMC, PCSK1 or LEPR deficiency, and later added Bardet-Biedl syndrome. In March 2026 the FDA added acquired hypothalamic obesity, which can follow brain tumors or their treatment, for adults and children 4 and older.
It is not approved for common obesity, and genetic testing or a confirmed diagnosis is needed. Common side effects include skin darkening, injection-site reactions, nausea and vomiting. The label also warns about depression and suicidal thoughts.
It is given as a daily injection under the skin and is prescribed by specialists.
Why it matters
Setmelanotide shows that some obesity has a single, treatable cause, but it is not a general weight-loss drug.
Related terms
Sources
Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error