What the human research shows
The clearest example on this site of a drug that is genuinely effective for the condition it was approved for and genuinely unimpressive for the condition it is sold for. The body-composition change is real, small, and comes with a documented cost.
Evidence profile0–5
- Metabolic & weight—0.0
- Cardiovascular—0.0
- Muscle & growthA1.7
- Healing & repair—0.0
- Neuro & sleep—0.0
- Immune & inflammation—0.0
- Sexual & hormonal—0.0
- Skin & appearance—0.0
- Ageing & longevityD0.0
| Outcome | Grade | Effect size | Human studies | Where the evidence comes from |
|---|---|---|---|---|
| Body composition in healthy older adults | AEstablished | Small | Meta-analysis, 18 study populations | Fat mass fell about 2.1 kg and lean mass rose about 2.1 kg, with no change in total body weight. A shift, not a loss — and smaller than most people expect.1 |
| Growth-hormone deficiency | AEstablished | Large | Approval-grade programmes | In children and adults with diagnosed deficiency, replacement restores growth and improves body composition and quality of life. This is the licensed indication and is not in dispute.2 |
| Anti-ageing | DNo human evidence | Not measurable | No trial supports it | No randomised trial has shown that growth hormone slows ageing or extends life in healthy people. The systematic review that examined the question concluded against the use.1 |
| Adverse effectsadverse | AEstablished | Moderate | Meta-analysis | Fluid retention, joint pain, carpal tunnel syndrome and breast tissue growth in men are all significantly more common, with a signal for new diabetes and impaired fasting glucose.1 |
Literature searched to 3 September 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.
Registered trials
ClinicalTrials.gov lists 89+ interventional studies naming Human growth hormone (somatropin) as an intervention — 58 completed, 7 recruiting, and 22 with results posted to the registry.
A registration is not a result. Anyone can register a study, and many never report — so this list shows what has been attempted, not what has been shown. The graded evidence above is the answer to whether something works.
81 further studies are registered. Participant counts marked * are the sponsor's estimate, not a final enrolment. Source: ClinicalTrials.gov, read directly from the registry and refreshed weekly.
What it is
Growth hormone is made by the pituitary and drives growth in childhood and tissue maintenance afterwards. Recombinant versions have been available since the 1980s and are standard treatment for deficiency, Turner syndrome, chronic kidney disease in children and a handful of other conditions.
Almost every peptide on this site that claims to build muscle does so by claiming to raise growth hormone. This page is what happens when you give people the hormone itself, at doses that certainly raise it.
How it is thought to work
It acts on growth-hormone receptors directly and drives IGF-1 production in the liver, which mediates most of the growth effects. In deficiency, restoring that signal restores normal physiology. In someone whose levels are already normal, adding more shifts body composition modestly and produces the adverse effects listed above.
What is still unknown
- Whether the small body-composition change translates into any functional benefit — strength and performance outcomes were inconsistently measured.
- Long-term cancer risk at supraphysiological IGF-1 levels, which is the theoretical concern behind cautious prescribing.
The molecule and how long it lasts
A 191-residue protein (somatropin) — no small-molecule record
- Route
- Subcutaneous injection, daily
- Half-life
- About 3 hours (subcutaneous)
- Licensed regimen (Genotropin (somatropin))
- Paediatric GHD: 0.16-0.24 mg/kg/week SC; adult GHD: about 0.2 mg/day (0.15-0.30 mg/day), increased by 0.1-0.2 mg/day every 1-2 months
From the approved product's prescribing information: Genotropin prescribing information (DailyMed) The regimen is the label's own wording, reproduced as a regulatory fact.
Regulatory status
Multiple somatropin products authorised for growth-hormone deficiency and related indications. Supply for physique or anti-ageing use is outside the licence.
Approved for specific deficiency indications. Distributing growth hormone for anti-ageing or athletic use is expressly unlawful under US law, not merely off-label.
Licensed by the MHRA for deficiency indications.
On the ARTG for deficiency indications; import without a prescription is an offence.
Authorised for deficiency indications.
Growth hormone is prohibited in and out of competition under the peptide-hormone class, and is specifically tested for.
Questions people actually ask
Does HGH build muscle in healthy adults?
Is HGH legal?
Why do so many peptides claim to raise growth hormone?
One page per claimed effect
- ADoes Human growth hormone (somatropin) help with body composition in healthy older adults?Meta-analysis, 18 study populations
- ADoes Human growth hormone (somatropin) help with growth-hormone deficiency?Approval-grade programmes
- DDoes Human growth hormone (somatropin) help with anti-ageing?No trial supports it
- AHow common is adverse effects with Human growth hormone (somatropin)?Meta-analysis
References
- 1Liu H, et al. Systematic review: the safety and efficacy of growth hormone in the healthy elderly.Ann Intern Med, 2007;146:104–11518 study populations; the definitive assessment of anti-ageing use.
- 2Somatropin prescribing information and approved indications.FDA / EMA product informationLicensed indications for growth-hormone deficiency.
Change log
- 2026-09-03Initial publication. Deficiency treatment graded A; anti-ageing use graded D on the systematic review.