Growth Hormone Secretagogues: Beyond Growth, Unveiling Diverse Human Effects

Growth hormone secretagogues (GHSs) are synthetic compounds designed to stimulate the body's natural release of growth hormone (GH). Historically, their primary focus has been on treating GH deficiency and related conditions. However, accumulating evidence suggested that GHSs might possess a wider array of physiological actions beyond just GH secretion, prompting a need to comprehensively review their full spectrum of endocrine and non-endocrine activities in humans.

The review consistently highlighted that GHSs are potent stimulators of growth hormone (GH) release, with studies demonstrating a significant increase in GH pulsatility, often reported as a 2- to 5-fold elevation in peak GH levels compared to placebo in healthy adults. This GH surge subsequently led to a robust increase in IGF-1 (Insulin-like Growth Factor 1) concentrations, typically ranging from 20% to 40% above baseline in chronic administration protocols. The most compelling aspect of the review was the comprehensive summary of emerging non-endocrine activities of GHSs, including their influence on appetite, metabolism, cardiovascular function, and immune responses, suggesting a much broader therapeutic potential than initially recognized. Specifically, the paper summarized evidence indicating GHSs could modulate appetite-regulating hormones like ghrelin, leading to observed changes in food intake and body composition, with some studies reporting modest weight gain of 1-2 kg over several weeks in certain cohorts. Furthermore, the review discussed preliminary data suggesting GHSs might exert direct effects on cardiac contractility and possess anti-inflammatory properties, potentially through mechanisms independent of GH release, although these non-endocrine effects were noted to be less consistently robust than their primary GH-stimulating action.