The Safety and Efficacy of Growth Hormone Secretagogues

Abstract

Introduction: Growth hormone (GH) increases lean body mass, decreases fat mass, increases exercise tolerance and maximum oxygen uptake, enhances muscle strength, and improves linear growth. Long-term studies of GH administration offer conflicting results on its safety, which has led to strict Food and Drug Administration criteria for GH use. The potential drawbacks of exogenous GH use are believed to be due in part to impaired regulatory feedback.

Aim: To review the literature on GH secretagogues (GHSs), which include GH-releasing peptides and the orally available small-molecule drug ibutamoren mesylate.

Methods: Review of clinical studies on the safety and efficacy of GHSs in human subjects.

Main outcome measure: Report on the physiologic changes from GHS use in human subjects including its safety profile.

Results: GHSs promote pulsatile release of GH that is subject to negative feedback and can prevent supra-therapeutic levels of GH and their sequelae. To date, few long-term, rigorously controlled studies have examined the efficacy and safety of GHSs, although GHSs might improve growth velocity in children, stimulate appetite, improve lean mass in wasting states and in obese individuals, decrease bone turnover, increase fat-free mass, and improve sleep. Available studies indicate that GHSs are well tolerated, with some concern for increases in blood glucose because of decreases in insulin sensitivity.

Conclusion: Further work is needed to better understand the long-term impact of GHSs on human anatomy and physiology and more specifically in the context of a diversity of clinical scenarios. Furthermore, the safety of these compounds with long-term use, including evaluation of cancer incidence and mortality, is needed. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev 2018;6:45-53.

Keywords: Growth Hormone; Growth Hormone Releasing Peptide; Growth Hormone Releasing Peptide-2; Growth Hormone Releasing Peptide-6; Growth Hormone Secretagogue; Hexarelin; Ibutamoren.