Beta-MSH

Where it comes from

Made in

POMC neurons of the hypothalamus, and the skin

Sent out by

With the other POMC products

Acts on

• Hypothalamic MC4R neurons
• Melanocytes

What it does

• Suppresses appetite through MC4R, and may be the main natural ligand for that receptor in the human hypothalamus ¹
• A POMC variant, Tyr221Cys, weakens its binding to MC4R and ran with obesity in the families carrying it ¹
• Its pigmentary effects are secondary to alpha-MSH, which binds MC1R far more strongly

In medicine

• None of its own; the MC4R medicines, setmelanotide among them, act on the receptor it shares with alpha-MSH
• It is measured only in research, and antibodies raised against it cross-react with the other melanocortins, so a reported level is hard to read ²

Beyond the body’s own use

• There is no beta-MSH product and no trial of one; what is asked of it is whether it, rather than alpha-MSH, sets appetite in people
• That question exists because human POMC is cut into beta-MSH and the mouse’s is not, so the mouse work that built melanocortin pharmacology could not test it ¹
• The evidence for a human role is the Tyr221Cys variant and the family studies around it, which is thin ground for a receptor as important as MC4R ¹
• Whether beta-MSH reaches the brain from the blood is unknown, and any attempt at a medicine would have to answer that first