Growth Hormone Secretagogues (GHSs) like Ibutamoren improve lean mass and sleep but require long-term safety data

Exogenous growth hormone (GH) is used to increase lean body mass, decrease fat, enhance muscle strength, and improve linear growth. However, long-term administration carries safety concerns and conflicting results, partly due to the disruption of the body's natural regulatory feedback loops. This has led to strict FDA criteria for its use. Growth hormone secretagogues (GHSs), a class including both GH-releasing peptides and orally active small molecules like ibutamoren mesylate, offer a potential alternative. They are being studied because they stimulate the body's own pulsatile release of GH, which remains subject to negative feedback, potentially avoiding the risks associated with supraphysiologic, non-pulsatile GH levels.

This paper conducted a literature review of clinical studies examining the safety and efficacy of growth hormone secretagogues (GHSs) in human subjects. The review included studies on various GHSs, such as GH-releasing peptides and the orally available small-molecule drug ibutamoren mesylate. The primary objective was to synthesize and report on the observed physiologic changes resulting from GHS administration in humans, with a specific focus on compiling a comprehensive safety profile based on the available clinical evidence.

The review found that Growth Hormone Secretagogues (GHSs) effectively promote a pulsatile release of GH, a pattern that is subject to the body's natural negative feedback mechanisms. This physiological action may prevent the supra-therapeutic GH levels and associated side effects seen with exogenous GH administration. Available studies, though limited in long-term scope, suggest GHSs are generally well-tolerated.

Key benefits observed across various studies include potential improvements in growth velocity in children, appetite stimulation, increased lean mass in wasting states and obese individuals, decreased bone turnover, increased fat-free mass, and improved sleep quality.

The most consistent concern noted was a potential increase in blood glucose levels due to decreases in insulin sensitivity. The authors conclude that despite these positive findings, the existing body of research lacks rigorously controlled, long-term data needed to fully establish the efficacy and safety profile of GHSs.

Written by TitrateLab, separately from the study summarized above.