Growth Hormone
A pituitary-secreted peptide hormone that stimulates cell growth, reproduction, and regeneration, and drives IGF-1 production in the liver.
Growth hormone is released from the anterior pituitary in pulsatile bursts, primarily during sleep and exercise, and acts both directly on tissues and indirectly by stimulating IGF-1 production in the liver. Many research peptides — GHRHs and GHRPs — are designed as secretagogues that amplify these natural GH pulses rather than replacing endogenous GH directly.
The distinction matters: GH secretagogue peptides work with the body’s feedback systems and preserve pulsatility, while exogenous recombinant HGH (rHGH) administration bypasses pituitary regulation entirely. Researchers studying body composition, recovery, and aging frequently focus on optimizing GH pulsatility as a more physiologically aligned approach than direct GH replacement.