Follistatin 344 vs Ghrelin

Binds and neutralizes myostatin (GDF-8) and activin; removes the natural brake on muscle growth allowing supraphysiological hypertrophy

A myostatin inhibitor that removes the natural limit on muscle growth. Produces dramatic increases in muscle mass and strength by blocking TGF-β family proteins.

Must be acylated at Ser3 (by GOAT enzyme) for GHSR-1a binding. Receptor activation in the pituitary stimulates GH release; hypothalamic action via NPY/AgRP neurons increases appetite and reduces energy expenditure.

An endogenous 28-amino acid peptide hormone produced primarily by gastric oxyntic cells. Functions as both the primary hunger signal and a potent GH secretagogue. The natural ligand for the growth hormone secretagogue receptor (GHSR-1a).