HGH

Origin and structure

Growth hormone is a protein of 191 amino acids, about 22 kDa, made by the pituitary gland at the base of the brain. It was first isolated from human pituitaries in 1956, and from the late 1950s children with severe deficiency were treated with hormone extracted from the glands of the dead; about 27,000 children worldwide received it. That ended in 1985, when former recipients began to develop Creutzfeldt-Jakob disease, a fatal prion disease carried over from infected donors. In all, 226 cases were linked to cadaver-derived growth hormone, most of them in France (119), the UK (65) and the US (29); two were in the Netherlands.

Recombinant production solved both the supply and the infection problem. Genentech's methionyl growth hormone, with one extra amino acid at the start, reached the US market in 1985; the somatropin used today has exactly the sequence of the natural hormone. Daily products include Genotropin, Norditropin, NutropinAq and Omnitrope, a biosimilar of Genotropin. Doses are written in milligrams; older texts and research vials use international units, and for somatropin 1 mg equals 3 IU.

The weekly versions are built to stay in the body longer. Somapacitan (Sogroya) has one amino acid swapped and a side chain that binds reversibly to albumin in the blood. Somatrogon (Ngenla) is growth hormone fused to short pieces of another human hormone, chorionic gonadotropin (hCG). Lonapegsomatropin (Skytrofa) is ordinary somatropin attached to a carrier that releases it slowly after injection. Strictly speaking, somapacitan and somatrogon are growth hormone analogues rather than somatropin itself.

How it works

Growth hormone binds to growth hormone receptors throughout the body. Most of its effects run through IGF-1 (insulin-like growth factor 1), which tissues, above all the liver, produce in response. In children it drives growth at the growth plates of the long bones for as long as these are open. In children and adults alike it promotes protein synthesis and shifts fat, carbohydrate and mineral metabolism: fat mass falls, lean mass rises, and the body becomes less sensitive to insulin.

Injected under the skin, daily somatropin has a half-life of 2 to 3 hours, which is why it is given every day, preferably in the evening. Somapacitan has a half-life of about 2 to 3 days in adults with deficiency, long enough for one injection a week; somatrogon and lonapegsomatropin also last long enough for weekly dosing. Doctors adjust the dose by the growth response and by blood IGF-1, aiming to keep IGF-1 within the normal range for age.

Is HGH approved?

Yes. Somatropin and its weekly analogues are authorised, prescription-only medicines in the EU, the Netherlands and the US, for clearly defined conditions. Treatment is started and monitored by specialists, and in adults the deficiency has to be confirmed by testing first.

Research-grade HGH, sold in vials labelled in IU for laboratory use, is not one of these medicines. It has no marketing authorisation and may not be used in people. The approvals below describe the branded products, not the research material.

• EU and the Netherlands, daily somatropin: authorised for children with growth hormone deficiency, Turner syndrome, chronic kidney disease, Prader-Willi syndrome or short stature after being born small for gestational age (SGA), for Noonan syndrome (Norditropin), and for adults with severe, proven deficiency. The Dutch Farmacotherapeutisch Kompas lists Genotropin, Norditropin, NutropinAq and Omnitrope.
• EU, weekly products: Sogroya (somapacitan) was authorised on 31 March 2021 and now covers children from 3 years and adults with deficiency. On 17 September 2026, after a re-examination, the EMA's CHMP recommended adding children born SGA, Noonan syndrome and idiopathic short stature; the European Commission had not yet decided when this page was checked. Skytrofa (lonapegsomatropin, 11 January 2022) and Ngenla (somatrogon, 14 February 2022) are authorised only for children and adolescents with deficiency from 3 years of age.
• US: the first recombinant growth hormone was approved in 1985. Current labels also cover idiopathic short stature and, for Serostim, HIV-associated wasting. Sogroya was first approved in 2020; its label, revised in February 2026, covers adults with deficiency and children from 2.5 years with deficiency, SGA, Noonan syndrome or idiopathic short stature. Skytrofa is approved for children and adults with deficiency, Ngenla for children. Distributing growth hormone as an anti-ageing treatment is illegal in the US.

What the research shows

The approvals rest on decades of trials in children and adults, and each weekly product was compared head to head with daily injections. The main results:

• Adults with deficiency (meta-analysis, 2004): across 37 blinded, placebo-controlled trials, growth hormone lowered fat mass by 3.1 kg, LDL cholesterol by 0.5 mmol/l and diastolic blood pressure by 1.8 mmHg, and raised lean mass by 2.7 kg, but fasting glucose rose by 0.2 mmol/l and insulin rose too. Whether this prevents heart attacks or deaths was not shown.
• Sogroya in adults (REAL 1): in 300 adults with deficiency, weekly somapacitan lowered the share of fat around the trunk by 1.06 percentage points after 34 weeks, against a rise of 0.47 on placebo. Daily somatropin lowered it more (2.23 points), while gains in lean mass and the fall in visceral fat were similar.
• Sogroya in children (REAL 4): 200 previously untreated children with deficiency grew 11.2 cm in a year on weekly somapacitan against 11.7 cm on daily somatropin, which met the trial's test for being no worse.
• Ngenla: in 224 children with deficiency, growth averaged 10.1 cm a year on weekly somatrogon against 9.8 cm on daily somatropin.
• Skytrofa (heiGHt): in 161 children aged 3 to 13, growth averaged 11.2 cm a year on lonapegsomatropin against 10.3 cm on daily somatropin, a statistically significant difference.
• Long-term safety after childhood treatment (SAGhE, 2020): 24,232 people treated as children in eight European countries, including the Netherlands, followed for more than 400,000 patient-years. In the low-risk group (isolated deficiency or idiopathic short stature) overall mortality was not raised (SMR 1.1, 95% CI 0.9 to 1.3), but deaths from circulatory and blood diseases were higher in all risk groups. Mortality was not related to the dose.

Anti-ageing and sport: what the trials found

Outside medical use, growth hormone is taken to build muscle, lose fat or slow ageing. Randomised trials in healthy people show modest changes in body composition, at the cost of more side effects, and in fit young adults no gain in strength or exercise capacity.

In sport, growth hormone, its analogues (lonapegsomatropin, somapacitan and somatrogon) and fragments such as AOD-9604 and hGH 176-191 are prohibited at all times under WADA class S2.2.3, and the Dutch anti-doping rules apply the same list.

• Healthy older adults (systematic review, 2007): 18 trial populations with 220 people on growth hormone, mean age 69, treated for a mean of 27 weeks. Fat mass fell by 2.1 kg and lean mass rose by 2.1 kg, with no change in weight, but swelling, joint pain, carpal tunnel syndrome and breast enlargement in men were more frequent, and new diabetes or impaired fasting glucose somewhat more likely. The authors concluded it cannot be recommended as an anti-ageing therapy.
• Fit young adults (systematic review, 2008): 27 study groups with 303 people on growth hormone, mean age 27, treated for a mean of 20 days. Lean mass rose by 2.1 kg, but strength and exercise capacity did not improve; lactate during exercise was higher in 2 of the 3 studies that measured it, and swelling and fatigue were more common.

Side effects and warnings

Many side effects stem from fluid retention and ease when the dose is lowered. In adults, swelling of the hands and feet, raised blood sugar, joint and muscle pain, headache and tingling each affect more than 1 in 10 people; stiffness, insomnia and carpal tunnel syndrome are common. Injection-site reactions are very common, and an underactive thyroid can surface during treatment.

The product information warns about raised pressure inside the skull (benign intracranial hypertension), a slipped growth plate at the hip and worsening scoliosis in children, pancreatitis and type 2 diabetes. Growth hormone must not be used with an active tumour, and in childhood cancer survivors it raises the risk of a second tumour, especially meningiomas after radiation to the head. Deaths have been reported in children with Prader-Willi syndrome who were severely obese or had breathing problems. In acutely critically ill patients, high doses of 5.3 to 8 mg a day increased mortality compared with placebo.

Frequently asked questions

Is HGH legal in the Netherlands?

Somatropin is a registered, prescription-only medicine in the Netherlands. Pharmacies supply products such as Genotropin, Norditropin, NutropinAq and Omnitrope on prescription, and a specialist starts treatment once tests have confirmed the diagnosis. Building muscle or slowing ageing is not an authorised use, and research-grade HGH is not a registered medicine, so it may not be sold or supplied for use in people. In sport it is prohibited, and even athletes with a diagnosed deficiency need a therapeutic use exemption.

Is HGH banned in sport?

Yes, at all times, in and out of competition. The 2026 WADA Prohibited List names growth hormone, its analogues lonapegsomatropin, somapacitan and somatrogon, and fragments such as AOD-9604 and hGH 176-191 in class S2.2.3. Substances that make the body release more of its own growth hormone, such as the peptides CJC-1295 and ipamorelin and the small molecule ibutamoren (MK-677), are banned under S2.2.4. The Dutch anti-doping rules apply the same list.

Does HGH build muscle?

It raises lean body mass, but that is not the same as stronger muscle. In a systematic review of 27 study groups of fit young adults, growth hormone added 2.1 kg of lean mass on average, while strength and exercise capacity did not improve. In adults who genuinely lack growth hormone, replacement shifts body composition towards less fat and more lean mass.

How many milligrams is 10 IU of HGH?

About 3.3 mg. For somatropin 1 mg corresponds to 3 international units (IU), so 24 IU is 8 mg and 36 IU is 12 mg. European labels give somatropin doses in milligrams; research vials are often labelled in IU.

What is the difference between HGH and CJC-1295 or ipamorelin?

HGH is the hormone itself. CJC-1295, an analogue of growth hormone-releasing hormone, and ipamorelin, a growth hormone secretagogue, are peptides that make the pituitary release more of its own growth hormone. Neither is an authorised medicine in the EU, and both are prohibited in sport under WADA class S2.2.4.

Is research-grade HGH the same as Genotropin or Omnitrope?

No. Genotropin and Omnitrope are licensed medicines with a known content per dose, made and tested under pharmaceutical rules. Research-grade HGH is sold for laboratory use only. It has no marketing authorisation, its identity and purity rest on the supplier's certificate of analysis, and it may not be used in people.

Storage and handling

Store according to product-label instructions and batch handling notes. Lyophilized research peptides are commonly kept dry, protected from light, and handled with clean laboratory technique.

References

Checked against these sources on 28 October 2026.

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