Metabolic Effects of a Growth Hormone-Releasing Factor in Obese Subjects with Reduced Growth Hormone Secretion: A Randomized Controlled Trial
Makimura H, Feldpausch MN, Rope AM, Hemphill LC, Torriani M, Lee H, Grinspoon SK
Journal of Clinical Endocrinology and Metabolism (2012) · n=60
Twelve months of tesamorelin in non-HIV abdominally obese adults with reduced GH secretion selectively reduced visceral adipose tissue without affecting subcutaneous fat, improved triglycerides and carotid intima-media thickness, and preserved glucose tolerance — the cleanest non-HIV reading of tesamorelin's metabolic effect available.
This is the Makimura et al. 2012 randomized controlled trial of tesamorelin in non-HIV abdominally obese adults with reduced growth-hormone secretion, conducted by Steven Grinspoon's Massachusetts General Hospital group — the same research program responsible for the bulk of the HIV-associated lipodystrophy tesamorelin literature (Falutz et al. 2007, Falutz et al. 2010, the Stanley tesamorelin-and-liver-fat series). Makimura is the bridge trial: the question being asked is whether tesamorelin's selective visceral-adipose-tissue reduction in HIV lipodystrophy generalizes to a non-HIV adult population where the underlying physiology is metabolic obesity with relative GH suppression rather than HIV-related adipose-tissue redistribution.
The design is the cleanest available non-HIV tesamorelin reading. Sixty abdominally obese adults (BMI ≥30, waist circumference >102 cm men or >88 cm women) with reduced GH secretion documented by standardized GHRH-arginine stimulation testing were randomized 1:1 to subcutaneous tesamorelin 2 mg daily or matching placebo for 12 months — substantially longer than the 26-week primary endpoint timeline that anchors most of the HIV-lipodystrophy work. The primary endpoint was change in visceral adipose tissue measured by single-slice abdominal CT. Pre-specified secondary endpoints included subcutaneous adipose tissue, anthropometric measures, lipid profile, carotid intima-media thickness as a surrogate marker of subclinical atherosclerosis, glucose tolerance by oral glucose tolerance test, and inflammatory markers (C-reactive protein).
The primary-endpoint result was positive: tesamorelin produced a 35 cm² reduction in visceral adipose tissue compared with no change on placebo (treatment effect approximately -1.7 kg fat mass and +1.4 kg lean mass), without affecting subcutaneous adipose tissue. The directionality and magnitude are consistent with the HIV-lipodystrophy trials, supporting the underlying mechanism — GHRH-receptor agonism producing pulsatile GH release, downstream IGF-1 elevation, and the GH-axis's characteristic preferential mobilization of visceral over subcutaneous fat. Triglycerides decreased on tesamorelin; carotid intima-media thickness (cIMT) improved on tesamorelin versus placebo (p=0.02) — the latter is one of the relatively rare surrogate-vascular-endpoint signals available for the tesamorelin program. C-reactive protein moved in a favorable direction. Glucose tolerance was preserved — a non-trivial finding given the GH axis's known capacity to worsen insulin sensitivity through downstream IGF-1 effects. No serious adverse events were reported, and discontinuation rates were comparable between arms.
The lean-mass finding (1.4 kg gain on tesamorelin) is the part that makes Makimura editorially relevant to sarcopenia-and-peptides. This is the cleanest tesamorelin lean-mass reading in a non-HIV adult population — and the population studied (abdominally obese adults with relative GH suppression) is one of the more plausible mechanistic candidates for a sarcopenia-adjacent indication. The trial was not designed around sarcopenia endpoints: it studied metabolic obesity, the lean-mass endpoint was secondary, and crucially the trial did not report a co-primary or pre-specified strength or function endpoint. Whether the 1.4-kg lean-mass change translates into a measurable strength or function effect under the EWGSOP2 framework is not addressed by Makimura and remains unanswered for the tesamorelin program. See the tesamorelin peptide page for the full clinical-trial corpus and the broader GH-axis mechanism context.
The trial is small (n=60) and single-center. Industry sponsorship by Theratechnologies is disclosed; the relationship between the MGH group and the sponsor is long-standing across the tesamorelin literature. The trial population is specific — abdominally obese adults with biochemically confirmed reduced GH secretion. Adults with normal GH responsiveness were not enrolled and the result does not directly generalize to them. The 12-month duration does not address the persistence-of-effect question past treatment discontinuation, which the HIV-lipodystrophy literature suggests is rapid rebound on cessation. Visceral-adipose-tissue measurement was by single-slice CT, the standard for the period but with known measurement-error properties. The lean-mass gain figure (1.4 kg) was secondary rather than primary and was not paired with a co-reported strength or function endpoint; whether the new lean tissue is contractile-functional muscle versus fluid or other lean compartment is not directly resolved by the trial. The cIMT improvement is a surrogate vascular endpoint and is consistent with — but not equivalent to — a cardiovascular outcome.
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