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HGH4.2
HGH (Somatropin) Research
Mostly mechanism / observationalLimited safety
7 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most HGH (Somatropin) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality meta-analyses and randomised trials published 1990–2014 with a typical study size of 131 participants.
Based on 7 studies · 1 meta-analysis · 2 RCTs · 3,648 total participants
Confidence
Moderate
By outcome
Body composition & lean mass
Mostly mechanism / observational6 studies
Aging & anti-aging (unproven)
Mostly mechanism / observational5 studies
Safety profile
Mostly mechanism / observational5 studies
Weight management
Mostly mechanism / observational3 studies
Performance & exercise capacity
Mostly mechanism / observational3 studies
Glucose & metabolic harm
Too few graded studies2 studies
Older research base
Newest study from 2014 · Latest meta-analysis: 2012
199020022014
1Systematic Review2007
GH cannot be recommended as an antiaging therapy.
Liu H, Bravata DM, Olkin I, Nayak S, Roberts B, Garber AM, Hoffman AR. · Annals of internal medicine (2007)
Systematic review and meta-analysis of randomized controlled trials of GH in community-dwelling healthy elderly (31 articles, 18 study populations, 220 GH recipients)
GH produced only small body-composition changes: fat mass fell ~2.1 kg and lean body mass rose ~2.1 kg, with no significant change in body weight, bone density, or most lipids
GH-treated participants were significantly more likely to experience soft-tissue edema, arthralgias, carpal tunnel syndrome and gynecomastia, and somewhat more likely to develop diabetes/impaired fasting glucose
Claims that growth hormone enhances physical performance are not supported by the scientific literature.
Liu H, Bravata DM, Olkin I, Friedlander A, Liu V, Roberts B, Bendavid E, Saynina O, Salpeter SR, Garber AM, Hoffman AR. · Annals of internal medicine (2008)
Systematic review of RCTs of GH in physically fit young people (44 articles, 27 study samples, 303 GH recipients), aged 13–45
Lean body mass increased ~2.1 kg with GH, but strength and exercise capacity did NOT improve, and lactate during exercise was higher — exercise capacity may even worsen
GH-treated participants more frequently experienced soft-tissue edema and fatigue
Because adverse effects were frequent (importantly, diabetes and glucose intolerance), GH interventions in the elderly should be confined to controlled studies.
26-week randomized, double-blind, placebo-controlled 2×2 factorial trial of GH and/or sex steroids in 131 healthy adults aged 65–88
GH increased lean body mass and decreased fat mass, but strength rose only marginally in men (with testosterone) and not significantly in women; endurance (VO2max) gains were small
Adverse effects were frequent: edema, carpal tunnel symptoms and arthralgias, and diabetes or glucose intolerance in 18 GH-treated men versus 7 not receiving GH
Growth hormone significantly increased sprint capacity ... other performance measures did not significantly change. The increase in sprint capacity was not maintained 6 weeks after discontinuation of the drug.
Meinhardt U, Nelson AE, Hansen JL, Birzniece V, Clifford D, Leung KC, Graham K, Ho KK. · Annals of internal medicine (2010)
WADA-funded randomized, placebo-controlled, blinded trial in 96 recreationally trained athletes; men received placebo, GH (2 mg/d), testosterone, or both
GH reduced fat mass and increased lean body mass — but the lean-mass gain was through an increase in extracellular WATER, not functional muscle
GH increased sprint capacity by ~3.9% (more with testosterone) but did NOT improve strength, power, or VO2max; the sprint gain disappeared within 6 weeks of stopping
There is a widespread misperception that PED use is safe ... PED use has been linked to an increased risk of death and a wide variety of cardiovascular, psychiatric, metabolic, endocrine, neurologic, infectious, hepatic, renal, and musculoskeletal disorders.
Pope HG Jr, Wood RI, Rogol A, Nyberg F, Bowers L, Bhasin S. · Endocrine reviews (2014)
Endocrine Society scientific statement synthesizing the medical consequences of performance-enhancing drug use, including growth hormone
Documents that illicit users take highly supraphysiologic doses, often combined with other agents, and that the adverse health effects are greatly underappreciated
Links PED use to increased mortality and to cardiovascular, metabolic, endocrine and other organ-system disorders — context for the metabolic and organomegaly harms of GH excess
The administration of human growth hormone for six months ... was accompanied by an 8.8 percent increase in lean body mass, a 14.4 percent decrease in adipose-tissue mass.
Rudman D, Feller AG, Nagraj HS, Gergans GA, Lalitha PY, Goldberg AF, et al. · The New England journal of medicine (1990)
The famous, much-overhyped study: 21 healthy men aged 61–81 with low IGF-1; 12 received GH (~0.03 mg/kg three times weekly) and 9 received no treatment for 6 months
GH raised IGF-1 into the youthful range and increased lean body mass by 8.8% and decreased adipose-tissue mass by 14.4%, with a small (1.6%) rise in lumbar bone density
A small, non-randomized controlled trial measuring body composition and IGF-1 — NOT function, strength, or longevity outcomes