HGH — Human Growth Hormone
Human growth hormone is made by the pituitary gland; its recombinant form has specific medical indications, distinct from anti-ageing uses.
Why does a hormone essential to growth prompt so many questions about ageing and performance? It depends on who is studied: a patient with deficiency or someone without it.
- Research Use Only
- Molecule under study
- Living document
- Current research state
- Somatropin is an established treatment for specific medical indications; cosmetic and anti-ageing uses do not have the same evidence.
- Current clinical phase
- Approved treatment for specific indications; limited studies outside them
- Last update
- 27 September 2026 · Reference fact sheet v1.0
- Living document
- Updated regularly as research progresses.
What is HGH — Human Growth Hormone?
HGH means Human Growth Hormone. The pituitary, a small gland at the base of the brain, produces it naturally. It contributes to growth, tissue and bone maintenance, and metabolism—how the body uses energy.
Natural GH is not the manufactured product, which is called somatropin. A true medical deficiency is diagnosed in a specific clinical context. The natural decline of GH with age is not, by itself, such a diagnosis. Bodybuilding and biohacking uses are a separate matter.
Names you may come across
Three related names, but different contexts: natural hormone, generic term and manufactured form.
English abbreviation for Human Growth Hormone.
Growth hormone naturally produced by the body.
Recombinant form of the human hormone, produced through biotechnology.
Understanding it simply
Interest in HGH spans medicine, body composition and ageing. The answer always depends on who was studied.
Diagnosed deficiency
Medical studies concern patients with confirmed deficiency, not everyone whose GH declines with age.
Body and performance
Lean mass, fat, strength and performance are different measures; a change in one does not guarantee the others.
Sleep and ageing
Deep sleep naturally coincides with GH peaks. This does not show that supplying GH improves sleep or extends life.
What research shows today
Science advances step by step. We clearly distinguish what is firmly established from what remains under study.
- GH is naturally released by the pituitary; IGF-1 mediates some of its effects. — established
- Somatropin has medical indications for certain confirmed deficiencies. — established
- A normal age-related decline in GH does not establish a medical deficiency. — established
- Long-term benefits in adults without deficiency remain uncertain. — ongoing
Strong evidence for certain diagnosed deficiencies; much more limited for adults without deficiency.
What the research shows
- In adults with confirmed GH deficiency, medical guidelines describe potential benefits for body composition, bones, exercise capacity and some aspects of quality of life.
- In older adults without diagnosed deficiency, studies sometimes show less fat and more lean mass. Lean mass includes water: it is not a direct measure of functional muscle or strength.
- GH influences fat metabolism; a change in body fat does not necessarily mean a loss of overall weight.
What still remains to be studied
- Somatropin has not been shown to slow ageing or extend life in people without deficiency.
- An increase in lean mass does not prove a lasting gain in strength or performance; studies in athletes do not support a general improvement.
- Documented risks include fluid retention and swelling, joint or muscle pain, tingling, numbness, carpal tunnel syndrome, elevated IGF-1 and reduced insulin sensitivity that can disturb blood sugar.
- Cancer: GH and IGF-1 are growth signals; active malignancy requires caution and is a contraindication in medical labelling. This does not show that HGH invariably causes cancer. Observational data cannot settle every long-term risk, especially outside approved indications.
What science shows
Physiology
- The pituitary releases GH in pulses; its direct effects and those of IGF-1 affect tissues, bones and energy use.
Confirmed deficiency
- In deficient patients, trials and guidelines support supervised treatment; benefits cannot automatically be applied to healthy people.
Adults without deficiency
- Body composition can change, but that does not demonstrate rejuvenation or a reliable improvement in strength.
Clinical trials
- Adult deficiency: patients with a confirmed medical diagnosis were studied; body composition, bones, exercise capacity and quality of life were assessed. Results apply to this specific group.
- Ageing: trials in older people without confirmed deficiency find modest changes in lean mass and fat, but no evidence of longer life; adverse effects are more common.
- Performance: a trial in healthy recreational athletes found a limited sprint signal, without a general gain in strength, power or endurance; this cannot be generalised to all athletes.
What we know today
Not all information carries the same weight of evidence. We therefore present it across three clearly distinct levels, from the most solid to the most indicative.
What scientific publications show
Scientific evidence- Results depend on the population: a deficient patient, an older adult without deficiency and a healthy athlete are not interchangeable.
What some professionals report
Documented- A single GH measurement is generally not enough for diagnosis because GH release varies throughout the day.
What the community reports
Field observations- Discussions about recovery, appearance or anti-ageing do not replace controlled trials.
Personal reports are presented separately from clinical evidence.
What does the medical community say?
- Medicine recognises specific indications for somatropin. Adult deficiency is diagnosed from clinical context and, usually, specific tests—not a single GH level.
- Cosmetic, bodybuilding or anti-ageing use does not have the same level of medical validation as treatment of confirmed deficiency.
Why biohacking is interested
- Biohacking and bodybuilding communities discuss sleep, recovery, fat, lean mass, skin, tissues and performance. The popularity of these uses sometimes exceeds the clinical evidence available in healthy people.
What people report online
Positive experiences mentioned
- Some report better sleep, a sense of faster recovery or gradual changes in body shape and skin.
Other experiences reported
- Others notice no effect or describe water retention, swelling, joint pain, tingling, numbness, carpal-tunnel-like symptoms, fatigue or altered blood sugar.
These are uncontrolled personal accounts. They cannot show that HGH caused an effect or measure its effectiveness.
What we know today
- GH is a natural hormone; somatropin has established medical uses in specific situations.
- It can change body composition; water retention, pain and blood-sugar changes are documented.
What we do not know yet
- Long-term benefit, longevity and overall anti-ageing effects in people without deficiency.
- Lasting functional gains in healthy people and the benefit–risk balance of prolonged off-label use.
How does HGH — Human Growth Hormone work?
The pituitary naturally releases growth hormone. GH acts directly on several tissues and also stimulates the liver to make more IGF-1.
Naturally releases GH, including during deep sleep.
Acts on tissues and influences how the body uses fats and other nutrients.
GH stimulates production of IGF-1, a separate signal involved in growth and tissues.
GH → tissues and IGF-1 production → effects on growth, metabolism and tissues. Natural IGF-1 is not IGF-1 LR3, a distinct modified molecule.
Clinical trials timeline
A molecule under study progresses step by step. Here, simply, is where the research currently stands.
- Medicine· 2011Completed
Adult deficiency guidelines
The Endocrine Society distinguishes deficient patients from people without a confirmed diagnosis.
- Research· 2007Completed
Ageing systematic review
In healthy older people, modest changes in body composition but more frequent adverse effects.
- Research· 2010Completed
Trial in recreational athletes
A sprint signal, without a general improvement in strength, power or endurance.
Available analyses
The theory is put to the test. Here are the independent analyses already published for HGH — Human Growth Hormone, available in the Analyses Library.
The analyses for this molecule are currently being compiled.
Open the analysis libraryFrequently asked questions
Are HGH and growth hormone the same thing?
Yes. HGH is human growth hormone; somatropin is its manufactured recombinant form.
Does HGH reduce body fat?
Some studies measure less fat in specific groups. This does not make HGH a general weight-loss treatment.
Does HGH build muscle and strength?
Higher lean mass can include water. It does not prove an increase in functional muscle or strength.
What is the difference between HGH and IGF-1?
GH comes from the pituitary and stimulates IGF-1 production, notably in the liver. IGF-1 LR3 is a different, modified molecule.
Is HGH really anti-ageing?
Not proven: changing body composition does not establish slower ageing or longer life.
Why do clinicians monitor IGF-1?
IGF-1 reflects part of GH activity and helps monitor medical treatment; an excessive rise calls for clinical assessment.
Scientific publications
Medical sources and human trials: their conclusions apply to the populations studied, not automatically to every use discussed online.
Glossary
- Pituitary gland
- Small gland at the base of the brain that releases growth hormone, among other hormones.
- IGF-1
- Signal made partly by the liver in response to GH; different from modified IGF-1 LR3.
- Lean mass
- Everything other than fat: muscles, water, bones and other tissues.
- Insulin resistance
- Reduced response to insulin, a hormone that helps regulate blood sugar.
Continue your discovery
Reference fact sheet — version 1.0, updated on 27 September 2026. The full regulatory and scientific framework is gathered in the “Important information” box at the top of the fact sheet.