Alpha-melanocyte-stimulating hormoneα-MSH

The core melanocortin ligand — pigment, appetite, inflammation.

EndogenousEstablished

Identity

Class: POMC-derived peptide (13 aa)
Source: Pituitary and hypothalamic POMC neurons; skin
Receptor: Melanocortin receptors MC1R, MC3R, MC4R, MC5R

Key properties

Molecular weight

~1,664.9 Da

Half-life (native)

~minutes (very short)

Model dosing

Approximate values for the native hormone. Engineered analogs are often deliberately larger and far longer-acting.

Mechanism

Cleaved from pro-opiomelanocortin (POMC), α-MSH activates several melanocortin receptors with strikingly different physiology by tissue: pigmentation via MC1R on melanocytes, energy balance via hypothalamic MC4R, and anti-inflammatory signaling more broadly.

Reference notes

The same ligand family produces different effects purely by which receptor it reaches.
POMC is processed tissue-specifically into α-MSH, ACTH, and other active peptides.
Receptor selectivity across MC1R–MC5R is the central design question for any melanocortin agonist.

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

1.Ligands for Melanocortin Receptors: Beyond Melanocyte-Stimulating Hormones and Adrenocorticotropin · Biomolecules, 2022 · PMID 36291616
2.Alpha-melanocyte-stimulating hormone and behavior · Neuroscience and biobehavioral reviews, 1982 · PMID 6294567