Is Bivamelagon legal in the United States?

An oral MC4R agonist being developed as a tablet counterpart to injected setmelanotide. A 28 person phase 2 in hypothalamic obesity completed in February 2026 with no results posted, and there is no peer reviewed publication on the compound at all.

Bivamelagon is an oral agonist of the melanocortin-4 receptor, the same receptor that setmelanotide activates by daily injection. It was discovered by LG Chem under the code LB54640 and licensed to Rhythm Pharmaceuticals, which is developing it for hypothalamic obesity, the weight gain that follows damage to the hypothalamus from tumours or their treatment.

Mechanism: In human pharmacology of the class, MC4R activation in the hypothalamus reduces appetite; this is the pathway that loss of function mutations in POMC, PCSK1 and LEPR disrupt upstream of the receptor, and that setmelanotide restores. Bivamelagon is described by its developer as a selective MC4R agonist that is orally bioavailable.

Regulatory history: Not FDA approved. Investigational; phase 2 complete in hypothalamic obesity with no results posted, open label extension enrolling (September 2026).

Approves prescription drugs by indication and polices unapproved products, including peptides sold online. Compounding pharmacies may prepare some compounds under a prescription when the FDA places them on a permitted bulk-substances category.

The classification above is the The Longevity Archive reading of U.S. Food and Drug Administration listings for Bivamelagon at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.