Somatropin

Recombinant human growth hormone, rhGH, GH, somatotropin; brand names include Genotropin, Norditropin, Humatrope, Nutropin, Saizen, Omnitrope, Zomacton, Serostim, Zorbtive; long-acting relatives: somapacitan (Sogroya), lonapegsomatropin (Skytrofa), somatrogon (Ngenla)

Growth hormone axis

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Note on this profile. Somatropin is an approved prescription medicine in essentially every country, not a research-only compound. This page explains the published science. Use outside a prescription — for anti-ageing, body composition or sport — is unapproved, is where most of the documented harm occurs, and in several countries is specifically illegal to supply for those purposes.

Summary

Class: Recombinant 191-amino-acid protein identical to the main form of human pituitary growth hormone
Mechanism: Binds the GH receptor on liver, muscle, bone and fat; drives IGF-1 production and acts directly to promote growth, protein synthesis, fat breakdown and reduced insulin sensitivity
Routes studied: Subcutaneous (standard); intramuscular (historical); intravenous (pharmacology only)
Dose range reported: Approved, children: roughly 0.16–0.3 mg/kg/week divided daily for GH deficiency; higher (up to ~0.47–0.48 mg/kg/week) for small-for-gestational-age and some other indications. Approved, adults with GH deficiency: start ~0.15–0.3 mg/day (or 0.004 mg/kg/day), titrate to IGF-1; typical maintenance 0.2–1 mg/day, lower in older adults and higher in young women. HIV wasting (Serostim): ~0.1 mg/kg/day up to 6 mg. Trials in healthy older adults: ~0.5–1 mg/day or 20–30 µg/kg three times weekly. Community (unapproved): 1–4 IU/day (0.33–1.33 mg); higher in bodybuilding contexts. 1 mg ≈ 3 IU
Half-life: Subcutaneous: terminal half-life ~2–4 hours, with GH detectable for 12–20 hours; IGF-1 effect persists for days. Long-acting analogues: weekly dosing
Storage: Approved products: refrigerate 2–8 °C before and, for most pens, after first use; some are room-temperature stable for a limited period — follow the label. Lyophilised vials: refrigerate; after reconstitution refrigerate and use within the labelled window (commonly 14–28 days)
Regulatory status: Approved medicine (US, EU, UK, AU, ZA and most other countries); prescription-only, with additional controls on non-medical supply in some jurisdictions

Doses are as reported in studies or by the community — never recommendations.

1What it is

Growth hormone is the pituitary hormone that drives growth in childhood and continues to regulate body composition and metabolism in adults. Until 1985 it was extracted from human cadaver pituitaries, which ended when cases of Creutzfeldt-Jakob disease were traced to contaminated extracts. Recombinant somatropin, made in bacteria or mammalian cells, replaced it the same year and is now produced by many manufacturers, including biosimilars (Omnitrope was the first biosimilar approved in the EU and US).

Approved uses are, broadly: growth failure in children (GH deficiency, Turner syndrome, Prader-Willi syndrome, chronic kidney disease, children born small for gestational age who do not catch up, idiopathic short stature, SHOX deficiency, Noonan syndrome — the exact list varies by country and brand); GH deficiency in adults; HIV-associated wasting; and short bowel syndrome. Everything else — anti-ageing, fat loss, muscle gain, recovery, sport — is off-label or outright prohibited, and that is where the bulk of community use sits.

2How it's thought to work

Liver. GH stimulates production of IGF-1, which mediates most of the growth and anabolic effects.

Bone and cartilage. promotes linear growth in children (via growth plates) and increases bone turnover in adults.

Muscle. increases protein synthesis and nitrogen retention; the increase in lean mass in adults is partly water and connective tissue, and strength gains are small or absent in trials.

Fat. stimulates lipolysis, reducing fat mass, especially visceral fat.

Glucose. GH is counter-regulatory to insulin — it raises blood glucose and reduces insulin sensitivity, which is why diabetes and glucose intolerance appear in trials and labels.

Fluid. causes sodium and water retention, producing the oedema, joint pain and carpal tunnel seen at higher doses.

Recombinant human growth hormone. One molecule brings two receptor chains together — the step that starts the signal in this family — and much of the effect is indirect, through IGF-1 made by the liver in response.Schematic — not to scale

3What the research shows

Growth in GH-deficient children

Decades of trials and registry data (KIGS, NCGS, GeNeSIS) show somatropin restores growth velocity and improves adult height in GH deficiency and the other paediatric indications; effect size varies by indication (Ranke 2018, Nat Rev Endocrinol review of registry data).

Adults with GH deficiency

Replacement improves body composition (less fat, more lean mass), lipid profile, bone density over years, exercise capacity and quality of life, with careful IGF-1-guided dosing (Molitch 2011, Endocrine Society guideline; Fleseriu 2019 update). [6]

Graded A (negative or marginal)

Healthy older adults ("anti-ageing")

Rudman 1990 (NEJM) gave GH to 12 men over 60 for six months and reported increased lean mass and skin thickness and decreased fat; the paper is the origin of GH anti-ageing marketing. Larger and longer trials since have been sobering. A systematic review of 31 studies (Liu 2007, Ann Intern Med) found ~2 kg more lean mass and ~2 kg less fat mass but no consistent improvement in strength, bone density or function, and high rates of oedema, joint pain, carpal tunnel and glucose intolerance/diabetes. Blackman 2002 (JAMA) found similar body-composition shifts with frequent adverse effects. [1][2][5]

Graded A (mostly negative)

Athletic performance

A systematic review (Liu 2008, Ann Intern Med) found GH increased lean mass but not strength or aerobic capacity in healthy young adults, with more fatigue and fluid retention. One found a modest improvement in sprint capacity (~4%) in recreational athletes, larger when combined with testosterone, that disappeared after stopping (Meinhardt 2010, Ann Intern Med). [3][4]

HIV wasting and short bowel syndrome

Approved on the basis of trials showing weight and lean mass gain in HIV wasting (Schambelan 1996, Ann Intern Med) and reduced parenteral nutrition needs in short bowel syndrome. [10]

Graded A (mixed; one major harm signal)

Recovery from injury, burns, critical illness

High-dose GH in critically ill adults increased mortality (Takala 1999, NEJM). Burns and some surgical populations show benefits on nitrogen balance and wound healing in children; this is not generalisable. [7]

Graded A/B

Long-term safety

The French SAGhE cohort of children treated with GH reported raised all-cause mortality driven by bone tumours, cardiovascular events and cerebrovascular haemorrhage at higher doses (Carel 2012, JCEM); the pooled European analysis found no overall increase in cancer mortality but signals for specific tumours and for stroke (Swerdlow 2017, Lancet Oncol). Interpretation remains debated; current consensus is that GH at approved doses in approved indications does not increase new cancer risk in people without prior malignancy, while higher-than-replacement exposure is not reassuring. [8][9]

4Reported side effects and interactions

Literature-reported

Common (literature). peripheral oedema, joint and muscle pain, carpal tunnel syndrome, paraesthesia, headache, injection-site reactions, raised fasting glucose and insulin. Dose-related and frequent at the doses used in anti-ageing and sport trials.

Serious / label warnings. new-onset type 2 diabetes or worsening of existing diabetes; benign intracranial hypertension (headache, visual change, nausea — usually early in treatment); slipped capital femoral epiphysis and scoliosis progression in growing children; pancreatitis (rare); hypothyroidism unmasked by increased T4-to-T3 conversion; adrenal insufficiency unmasked (GH increases cortisol clearance); fluid retention sufficient to cause heart failure in susceptible people; increased mortality in acute critical illness; second neoplasm in childhood cancer survivors (small absolute increase in registries); contraindicated with active malignancy, active proliferative diabetic retinopathy, and in Prader-Willi children with severe obesity or respiratory impairment (sudden death reports).

Community-reported

Community-reported (unapproved use). water retention and "puffiness", numb or tingling hands, joint ache, lethargy, raised fasting glucose, vivid dreams; overt hypoglycaemia is not a GH effect and usually reflects co-use of insulin.

With chronic supraphysiological use. acromegaly-like changes — jaw and hand growth, soft-tissue overgrowth, sleep apnoea, cardiomyopathy, insulin resistance; these are documented in bodybuilders and are not reversible.

Counterfeits. GH is one of the most counterfeited injectables; mislabelled vials (including HCG or nothing sold as GH) are repeatedly documented by regulators and in testing programmes.

Interactions. glucocorticoids blunt growth response and GH increases cortisol clearance; oral oestrogen reduces IGF-1 response (women on oral oestrogen need higher doses); insulin and oral hypoglycaemics may need adjustment; GH alters metabolism of some drugs via CYP450 induction; thyroid hormone needs may change.

Markers researchers commonly monitor

These follow the approved-label monitoring and trial protocols and are better established than for any other compound in this category:

Marker	Why it's watched
IGF-1	the dosing marker. Labels and guidelines titrate to keep IGF-1 within the age- and sex-adjusted normal range; levels above the upper limit are associated with the adverse effects above.
Fasting glucose, fasting insulin, HbA1c	GH reduces insulin sensitivity; the main metabolic safety markers.
Free T4 and TSH	GH can lower free T4 and unmask central hypothyroidism.
Morning cortisol (with ACTH if indicated)	GH increases cortisol clearance and can unmask adrenal insufficiency, particularly in pituitary disease.
Lipid panel	LDL often falls with replacement; useful for tracking benefit.
Blood pressure, body weight, ankle oedema	fluid retention is dose-limiting.
Fundoscopy	if headache or visual symptoms develop (intracranial hypertension); and for diabetic retinopathy in people with diabetes.
Body composition (DEXA)	lean and fat mass are the outcomes studied; scale weight alone is misleading because of water.
Bone density	in adult GH deficiency, every 1–2 years.
Age-appropriate cancer screening	not GH-specific, but labels advise it, and anyone with a cancer history needs specialist input.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Approved pens and cartridges come pre-mixed or with a built-in system; follow the label and do not shake. Generic vials (usually labelled in IU, commonly 10 IU per vial) are with bacteriostatic or sterile water; the units problem is real — 1 mg ≈ 3 IU, and pens are labelled in mg while most grey-market product is labelled in IU. Use the calculator and check the unit setting.

Open in calculator, pre-loaded →

6Commonly studied alongside

Testosterone (Blackman 2002; Meinhardt 2010 — combination increased adverse effects); IGF-1 as the downstream marker; levothyroxine and hydrocortisone in panhypopituitary patients. Community pairing with insulin, GH secretagogues (ipamorelin, CJC-1295, MK-677) or GLP-1 agonists has no trial basis. GH secretagogues are an alternative to, not an addition to, GH itself — adding GH suppresses the endogenous pulse the secretagogues are meant to amplify.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved (multiple brands and biosimilars). Federal law (21 USC 333(e)) specifically makes distributing GH for any use other than an approved indication a criminal offence, a provision unique to GH and anabolic steroids
European Union	EMA-authorised, including biosimilars; prescription-only
United Kingdom	MHRA-licensed; prescription-only; NICE guidance restricts NHS use to defined indications
Australia	TGA-approved; Schedule 4; PBS access restricted to approved indications under the GH programme
South Africa	SAHPRA-registered; Schedule 4
Sport	Prohibited by WADA (S2) at all times; detected by isoform ratio and biomarker (IGF-1 / P-III-NP) tests

8Open questions

Whether long-acting weekly GH analogues change the safety profile over decades.
The true long-term cancer and cerebrovascular risk after childhood treatment (SAGhE is suggestive, not conclusive).
Whether any dose of GH in healthy adults improves function rather than just body-composition numbers; the trial evidence so far says no.
How much of community "GH" is actually GH.

9References

1Rudman D et al. (1990). Effects of human growth hormone in men over 60 years old. N Engl J Med. PubMed · DOI
2Liu H et al. (2007). Systematic review: the safety and efficacy of growth hormone in the healthy elderly. Ann Intern Med. PubMed · DOI
3Liu H et al. (2008). Systematic review: the effects of growth hormone on athletic performance. Ann Intern Med. PubMed · DOI
4Meinhardt U et al. (2010). The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial. Ann Intern Med. PubMed · DOI
5Blackman MR et al. (2002). Growth hormone and sex steroid administration in healthy aged women and men: a randomized controlled trial. JAMA. PubMed · DOI
6Molitch ME et al. (2011). Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. PubMed · DOI
7Takala J et al. (1999). Increased mortality associated with growth hormone treatment in critically ill adults. N Engl J Med. PubMed · DOI
8Carel JC et al. (2012). Long-term mortality after recombinant growth hormone treatment for isolated growth hormone deficiency or childhood short stature: preliminary report of the French SAGhE study. J Clin Endocrinol Metab. PubMed · DOI
9Swerdlow AJ et al. (2017). Cancer risks in patients treated with growth hormone in childhood: the SAGhE European cohort study. Lancet Oncol (and companion papers). PubMed · DOI
10Schambelan M et al. (1996). Recombinant human growth hormone in patients with HIV-associated wasting: a randomized, placebo-controlled trial. Ann Intern Med. PubMed · DOI
11Pfizer. Genotropin (somatropin) prescribing information (current label); Novo Nordisk. Norditropin prescribing information (current label). PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

10Community

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Self-reported side effects Phase 2

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11Page history

26 Oct 2026Profile published — awaiting medical review

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