Growth hormone (hGH) & IGF-1
Also known as: hgh, somatropin, igf-1
A prescription hormone with a real medical role and a physique reputation that the human evidence does not support.
Legal status: UK: prescription-only medicine; legitimately available only via a doctor's prescription. Checked 2026-07-26.
Prohibited in sport: Yes — on the WADA Prohibited List.
Approved medical use: Licensed for diagnosed growth-hormone deficiency in children and adults, and for specific conditions such as Turner syndrome and Prader-Willi syndrome.
What it is
Growth hormone is produced by the pituitary gland, mostly during deep sleep, and many of its effects on tissue are mediated by IGF-1 made in the liver in response to it. Recombinant human growth hormone is a licensed medicine for diagnosed deficiency. In a performance context it is used for body composition and for claimed anti-ageing and healing effects.
On the NHS it is prescribed for children with growth-hormone deficiency and for adults meeting strict severity and quality-of-life criteria, under endocrinology supervision.
What’s claimed
- Muscle gain alongside fat loss
- Faster healing of injuries, including tendon and joint
- Anti-ageing effects on skin, sleep and energy
What the evidence shows
This is the clearest gap between reputation and evidence in the library. Growth hormone in deficient people is genuinely transformative. In healthy adults, controlled trials show it increases lean body mass, but largely through fluid retention rather than contractile tissue, with little or no measurable gain in strength, and some studies finding exercise capacity worsened. The fat-loss effect is real but modest. The healing claims are largely untested in humans (Bronze). The anti-ageing claims trace to a small 1990 study whose authors and journal have both since publicly cautioned against how it has been used to sell the idea.
The risks
- Metabolic: growth hormone raises blood glucose and reduces insulin sensitivity, and sustained use is associated with the development of type-2 diabetes.
- Musculoskeletal: fluid retention, joint pain, and carpal tunnel syndrome are common and dose-related.
- Cardiac: acromegalic changes with prolonged supraphysiological use, including cardiac enlargement.
- Growth of existing tissue: because it promotes cell growth generally, there are theoretical and debated concerns about pre-existing tumours.
- Counterfeits: it is expensive and heavily counterfeited; illegitimate product may contain nothing, or something else entirely.
What needs monitoring
- IGF-1, which is the practical measure of growth-hormone status
- Fasting glucose and HbA1c
- Blood pressure and cardiac review with sustained use
- This is a specialist prescription medicine, and endocrinology supervision is what makes its legitimate use safe.