glp 1 mechanism of action diagram GLP-1 Recent updates on GLP-1 agonists:

What forms the bulk of the retail price2 of peptides is not the cost of manufacturing, but the capital infrastructure: the regulatory burden, the cold chain logistics, the pen device (which sometimes costs more than the drug itself), and, above all, the return needed to justify $9 billion in the initial R&D of these GLP-1 drugs

Eur.J.Gastroenterol 1990;2:351-355

But they're in a completely different league than what's being hawked on underground websites

Melanotan 2 is non-selective, activating MC1R through MC5R, which adds libido enhancement and appetite suppression but also produces more side effects including nausea, spontaneous erections, and higher rates of new mole formation