Somatropin (HGH 191AA): what the trials show, status and safety

Summary

Somatropin is human growth hormone made in the laboratory, a chain of 191 amino acids with the same sequence as the hormone from the pituitary gland. It has been an approved, prescription-only medicine since October 1986, and it is prescription-only in all seven markets checked here. The grey-market name HGH 191AA is not a grade or a purity claim: every licensed product is 191AA. In healthy people two independent systematic reviews found no gain in muscle strength and none in maximal oxygen uptake, while swelling and exhaustion became more common. In the United States, supplying growth hormone for any use other than an approved medical condition is a federal offence.

Key findings at a glance

• A licensed medicine for forty years, not a research compound. The American register holds twelve applications with somatropin as the active ingredient, the oldest approved on 16 October 1986 ^[1].
• 191 amino acids is the standard, not a grade. Every approved product is a single chain of 191 residues with two internal disulfide bridges, matching the pituitary hormone exactly ^[2], ^[3].
• Prescription-only in all seven markets, with criminal law on top. Australia forbids possession without authority ^[4], a German ordinance sets 16 mg as the quantity from which possession alone is an offence ^[5], and American federal law punishes non-approved supply with up to five years in prison, ten where a person under 18 is involved ^[6].
• No performance gain in healthy people. Across 303 fit adults, lean mass was 2.1 kg higher, strength and exercise capacity were not, lactate during exercise was higher, and swelling and exhaustion were more common ^[7]. A meta-analysis in 254 young adults found no change in strength or oxygen uptake ^[8].
• No anti-ageing benefit either. In 220 healthy older adults, body weight stayed unchanged at plus 0.1 kg, while swelling, joint pain and carpal tunnel syndrome became significantly more common; the review measured small shifts in fat and lean mass of 2.1 kg each and still concluded that growth hormone cannot be advised as an anti-ageing therapy ^[9].
• Long-term deaths are only partly explained. In 24,232 patients treated as children, followed for more than 400,000 person-years, mortality in the low-risk group was not raised, at 1.1 times the general population, but deaths from circulatory and blood disorders were raised in every risk group ^[10].
• Banned in sport at all times. Growth hormone has its own named section on the 2026 prohibited list, S2.2.3, and everything in that class is a non-specified substance ^[11].

What it is

Somatropin is recombinant human growth hormone. The molecule is not an analogue and not a fragment, but the complete human hormone, produced either in the bacterium Escherichia coli or in a mouse cell line, depending on the manufacturer ^[3], ^[12]. Regulators treat it as a biological medicine rather than a chemical one, which is why it carries a biologics licence in the United States, schedule D status in Canada and the biotechnology category in Switzerland ^[1].

The grey-market name HGH 191AA is not an official one. It counts the amino acid building blocks in the chain, and it exists to mark the contrast with a 192-amino-acid form sold in the 1980s.

That earlier form carried one extra methionine at the front, left over from the bacterial start signal in the first production methods. It is a separate substance with its own name, somatrem, and its own code ^[13], ^[14]. Somatrem is no longer marketed.

Ten brands appear on the American register with at least one presentation still listed as prescription: Genotropin, Norditropin, Humatrope, Omnitrope, Saizen, Zomacton, Serostim, Zorbtive, Nutropin and Nutropin AQ ^[1], ^[15], ^[16]. Two further applications, for Nutropin in its first form and for Accretropin, are wholly discontinued ^[1]. Omnitrope was also the first biosimilar authorised across the European Union ^[17].

Quick facts

How it works

Somatropin is therapeutically equivalent to the growth hormone the pituitary gland releases, and it works through two routes at once.

• It binds the growth hormone receptor, which sits on liver cells, cartilage, bone, muscle and fat cells, and acts on those cells directly ^[3].
• It raises IGF-1, a messenger substance made mainly in the liver, and much of the growth effect arrives that way ^[3].
• It acts on the way the body handles protein, bone and cartilage, and it increases the breakdown of stored fat ^[3].
• It lowers sensitivity to insulin, which is the reason diabetes can become visible under treatment ^[3].
• It blocks an enzyme that converts cortisone into cortisol, so people on steroid replacement may need a different amount of it ^[3].

This is what separates somatropin from the substances that merely ask the body for more of its own hormone. Sermorelin, tesamorelin and the secretagogues act one step earlier, on the pituitary gland; somatropin is the hormone itself. The anti-doping list keeps the two families in separate sections for exactly that reason ^[11], ^[13].

What the trials found

The approvals rest on trials in diagnosed patients, mostly children with measured growth disorders. The questions the grey market asks, about healthy adults, were answered separately and negatively.

Children with idiopathic short stature

RCT One randomised, open trial enrolled 177 children and followed them to their final adult height, with a median of 5.7 years of treatment. Of the 105 who were still prepubertal when they were randomised, the average age was 11.4 years (standard deviation 1.3) and height was 2.4 standard deviations below the norm (0.4), with a growth speed of 4.4 cm a year (0.9). The final-height analysis covered 102 children in three groups: 30 untreated, 30 in the lower arm and 42 in the higher one.

Measured against their own starting point, the untreated children gained 0.41 standard deviations, with a spread of 0.58; the lower arm gained 0.95 (0.75) and the higher arm 1.36 (0.64). Against the untreated control group, the gain in final height score was 0.53 standard deviations in the lower arm (95 per cent confidence interval 0.20 to 0.87; p = 0.0022). It was 0.94 in the higher arm (0.63 to 1.26; p < 0.0001).

Measured against the height that had been predicted for them, the three groups gained 0.23 (0.66), 0.73 (0.63) and 1.05 (0.83) standard deviations, which makes the difference against the control group 0.60 (0.09 to 1.11; p = 0.0217) and 0.90 (0.42 to 1.39; p = 0.0004).

Across both treated arms the observed gain in final height against untreated controls was 9.8 cm in girls and 5.0 cm in boys. A gain of one full standard deviation occurred in 10 per cent of untreated children, 50 per cent in the lower arm and 69 per cent in the higher one.

The trial was open, with no dummy injection, and every participant had a diagnosed growth disorder ^[3].

Children born small for gestational age

RCT Four randomised, open trials treated 209 children aged two to eight who had not caught up in growth, over 24 months. Height scores moved from 3.2 standard deviations below the norm to 2.0 in the lower arm of 40 children, and from 3.4 to 1.7 in the higher arm of 76.

That is a gain of 1.2 standard deviations in the lower arm, with a spread of 0.5, and of 1.7 in the higher one (0.6). The 93 untreated children moved from 3.1 to 2.9, a change of plus 0.1 (0.3). Both treated arms differed from the control group at p = 0.0001, and the higher arm also differed from the lower one ^[3].

Children with Prader-Willi syndrome

RCT Two small randomised, open trials compared treated against untreated children in the first year. In the first, 15 treated children grew 11.6 cm (standard deviation 2.3) against 5.0 cm (1.2) in 12 untreated ones (p ≤ 0.001). In the second the figures were 10.7 cm (2.3) in 7 children against 4.3 cm (1.5) in 9.

Height scores tell the same story. Under treatment they moved from 1.6 standard deviations below the norm to 0.5 below it, while the untreated children went from 1.8 below it to 1.9. The difference in that movement was significant (p ≤ 0.002).

Body composition moved as well. Fat mass fell by 0.9 kg (2.2) against a rise of 2.3 kg (2.4) without treatment (p < 0.005). Lean mass rose by 4.7 kg (1.9) against 0.7 kg (2.4).

Body weight changed almost identically in both groups, by plus 3.7 kg (2.0) against plus 3.5 kg (1.9), which was not significant. Bone age did not accelerate ^[3].

Girls with Turner syndrome

RCT Two randomised, open trials followed 38 girls for 12 months without a control group. In the 22 girls of the trial that used the larger amount, growth speed rose from 4.1 cm a year (standard deviation 1.5) to 7.8 (1.6), a change of plus 3.7 (95 per cent confidence interval 3.0 to 4.3).

In the 16 girls of the trial that used the smaller amount it rose from 3.9 (1.0) to 6.1 (0.9), a change of plus 2.2 (1.5 to 2.9). Height scores improved by 0.4 and 0.3 standard deviations respectively, all changes at p < 0.05.

Measured against a Turner-specific reference rather than the general one, the same data yield larger gains, of 0.8 and 0.5 ^[3].

Adults with growth hormone deficiency

RCT Six randomised trials in 172 adults compared treatment against placebo for six months, then continued openly for up to 24. Lean mass, total body water and the ratio of lean to fat mass all rose, while total body fat and waist size fell, and the effects held beyond six months.

Bone mineral density dropped at six months and was back at starting values by twelve. The label reports no numbers for these endpoints, and the trials measured body composition rather than fractures, heart attacks or survival ^[3].

Healthy adults: strength and endurance

Systematic review A review of 27 study samples drawn from 44 articles covered 303 physically fit people aged 13 to 45, average age 27 (standard deviation 3), lean at an average body mass index of 24 (2) and fit at an average maximal oxygen uptake of 51 ml per kilogram per minute (8). Total treatment across the whole evidence base came to 13.3 person-years.

Lean body mass was 2.1 kg higher than in control groups (95 per cent confidence interval 1.3 to 2.9). Strength and exercise capacity did not improve.

Lactate during exercise was significantly higher in two of the three studies that measured it, and soft-tissue swelling and exhaustion were more common under treatment. Its authors write that claims of enhanced physical performance are not supported by the scientific literature ^[7].

Meta-analysis An independent meta-analysis of 11 placebo-controlled trials, picked from 54 candidate articles, covered 254 healthy young adults and reached the same place by another route. Lean mass rose and fat mass fell (both p < 0.01). Glycerol (p = 0.01) and free fatty acids (p < 0.01) during exercise rose, while the respiratory quotient did not change (p = 0.30).

Over weeks to months there was no improvement in muscle strength (p = 0.36) and none in maximal oxygen uptake (p = 0.89). Anaerobic capacity rose in the single trial that measured it (p < 0.01) ^[8].

Healthy older adults: the anti-ageing question

Systematic review A review of 31 articles covering 18 study populations examined 220 healthy older adults, average age 69 (standard deviation 6) and overweight at an average body mass index of 28 (2), treated for an average of 27 weeks (16), which adds up to 107 person-years. Fat mass fell by 2.1 kg (95 per cent confidence interval 2.8 to 1.35) and lean mass rose by 2.1 kg (1.3 to 2.9), both at p < 0.001.

Body weight did not change, at plus 0.1 kg (minus 0.7 to 0.8; p = 0.87). Total cholesterol fell by 0.29 mmol per litre (p = 0.006), but the fall was no longer significant once the change in body composition was taken into account. Bone density and the other blood fats stayed where they were.

Soft-tissue swelling, joint pain, carpal tunnel syndrome and breast tissue growth in men were all significantly more common, and new diabetes and impaired fasting glucose showed the same tendency. Its authors concluded that growth hormone cannot be advised as an anti-ageing therapy, and noted that supplying it for that purpose is illegal in the United States ^[9].

Long-term mortality

Observational The largest cohort followed 24,232 people treated as children in eight European countries for more than 400,000 person-years, with risk groups defined in advance by their underlying condition. In the low-risk group, those with isolated growth hormone deficiency or idiopathic short stature, overall mortality was not significantly raised, at 1.1 times the general population (95 per cent confidence interval 0.9 to 1.3).

It was 1.5 times higher in those born small for gestational age (1.1 to 1.9), a result the authors trace to the French part of the cohort alone. It reached 3.8 times in the moderate-risk group (3.3 to 4.4) and 17.1 times in the high-risk group (15.6 to 18.7).

Mortality was not associated with the amount given in any risk group. Deaths from circulatory and blood disorders were raised in every one of them ^[10].

Observational An earlier French analysis of 6,928 patients treated between 1985 and 1996 found overall mortality raised by a third, at 1.33 times the general population (1.08 to 1.64).

Cancer deaths overall were not raised, but bone tumour deaths were, at 5.00 times (1.01 to 14.63). Deaths from circulatory disease were raised at 3.07 times (1.40 to 5.83), and deaths from bleeding in or around the brain at 6.66 times (1.79 to 17.05).

That analysis also found higher mortality in the patients who had received most of the hormone each day: 2.94 times the general population (1.22 to 7.07), a hazard ratio of 2.79 (1.14 to 6.82) once height was accounted for. The larger cohort of 2020 did not confirm that association, and whether it was an artefact of the French data remains open ^[10], ^[20].

Observational A cancer analysis of the same European cohort found raised incidence and mortality at several sites. That was largely driven by second tumours in people given growth hormone after cancer treatment. Among patients with a growth disorder and nothing else, only bone and bladder cancer incidence was significantly raised.

Cancer risk was independent of treatment duration and cumulative amount. In those with a previous cancer, cancer mortality rose significantly with higher daily amounts (p for trend < 0.001). Hodgkin lymphoma incidence rose with longer follow-up (p for trend 0.001).

Its authors said the findings did not support a cancer-causing effect, but that the unexplained trends need further work ^[21].

What is still unknown

• Whether replacement in adults changes anything that matters. The approval trials measured body composition, not fractures, heart attacks or survival ^[3].
• What the raised circulatory and blood-disorder mortality in every risk group means, given that the underlying conditions cannot be separated from the treatment ^[10].
• Why cancer mortality tracked daily amounts in patients with a previous cancer, and why bone and bladder cancer and Hodgkin lymphoma showed the trends they did ^[21].
• How the substance behaves in kidney or liver failure, which has never been studied ^[3].
• Whether any endpoint improves in healthy people. No published trial shows a performance or anti-ageing benefit, while the side-effect burden is documented ^[7], ^[8], ^[9].
• What is actually inside grey-market material. Almost nothing substance-specific is published, and the available analyses come from seizures with no claim to be representative ^[22], ^[23].

Side effects and safety

The safety picture comes from the official American product information and the long-term cohorts, and it is substantial in both directions.

• Swelling in 17.5 per cent against 5.1 per cent on placebo in the first six months, in 573 treated adults against 572 on placebo (p ≤ 0.025). The table behind these figures covers 1,145 adults in the approval trials ^[3].
• Joint pain in 17.3 per cent against 4.2 per cent. Pain in an arm or leg affected 14.7 per cent against 5.9 per cent, stiffness 7.9 per cent against 1.6 per cent and muscle pain 4.9 per cent against 1.6 per cent ^[3].
• Tingling in 9.6 per cent against 1.9 per cent. Swelling recorded separately as peripheral oedema affected 10.8 per cent against 2.6 per cent, headache 9.9 per cent against 7.7 per cent and exhaustion 5.8 per cent against 3.8 per cent ^[3].
• Carpal tunnel syndrome in 61 of 3,031 patients (2.0 per cent) in the long-term extension studies. It eased in 52 of them after the amount was lowered or treatment paused, and nine had surgery ^[3].
• New diabetes in 12 of 3,031 patients (0.4 per cent), all of whom already had risk factors, either a raised long-term blood sugar reading or marked obesity ^[3].
• IGF-1 pushed above the normal range. In the short stature trial, at least one reading more than two standard deviations high occurred in 3 per cent of untreated children, 30 per cent in the lower arm and 38 per cent in the higher one. Two or more consecutive readings that high occurred in none of the untreated children, 7 per cent of the lower arm and 14 per cent of the higher one ^[3].
• Antibodies against the hormone in 8 of 413 children (1.9 per cent), none above a binding capacity of 2 mg/L and none with a reduced growth response ^[3].

Several situations rule the medicine out entirely. They are critical illness after heart or abdominal surgery, multiple trauma or acute respiratory failure, and active cancer. The others are a known allergy, active or severe diabetic eye disease, and closed growth plates in children. The British product information adds any sign of tumour activity ^[3], ^[24].

One contraindication carries a death risk in plain terms. The medicine must not be used in children with Prader-Willi syndrome who are severely obese, have a history of blocked upper airways or sleep apnoea, or are severely breathing-impaired. Sudden deaths have been reported in that group ^[3].

Further warnings cover second tumours in childhood cancer survivors who had cranial radiation, most often meningiomas inside the skull. Another covers raised pressure inside the skull with swelling of the optic disc, usually within the first eight weeks.

The label also warns about a slipped growth plate at the hip, which can destroy the bone head, and about severe allergic reactions including angioedema ^[3].

One historical event still shapes the substance. The predecessor product, growth hormone extracted from the pituitary glands of cadavers, was contaminated with the prions that cause Creutzfeldt-Jakob disease. Recipients developed that disease, and in 2024 an iatrogenic form of Alzheimer's disease with matching biomarkers was described in survivors as well ^[25].

Avoiding that contamination is the reason recombinant material replaced the extracted kind, and it is the real origin of the 191AA label.

Known gaps remain. There are no data on the substance in kidney or liver failure and no hard-endpoint evidence for adult replacement. In the long-term cohorts, the effect of treatment cannot be separated from the effect of the underlying condition ^[3], ^[10].

Why this page lists no doses

Somatropin is a prescription-only medicine in every market covered here, and in the United States supplying it for anything other than an approved condition is a criminal offence ^[6]. Choosing an amount belongs in the official product information and with the treating doctor, so this page reports what the trials measured without repeating the amounts they used. Where a study compared two levels, the arms are named only as the lower and the higher one.

Two numbers on this page are nevertheless written in the units a dose would use, because in both cases the number itself is the finding. One is the 16 mg threshold in German law, above which possession alone is an offence ^[5]. The other is the antibody binding capacity of 2 mg/L that, according to the American product information, none of the antibody-positive children in the approval trials exceeded ^[3]. Neither describes how much of the medicine anyone is given.

Development and approval status

Somatropin is not an investigational substance. It has been licensed for four decades, in ten approved conditions across three medical fields, and the active research has moved on to longer-acting molecules with different names and to the long-term safety of people already treated.

Three rows need a word of explanation. The British register returns 607 documents for the substance, including 144 product information sheets and named licences for five brands, but it gives no first approval date, so the row above says only that ^[30]. The German and European rows carry the date of the first licence that covers the whole European Union; the national approvals in both are older than that, and no single starting date covers them ^[17]. The Australian row is undated because the scheduling decision is much older than the instrument that currently carries it; 27 May 2026 is the day that instrument was made ^[4].

German prescription status follows from the substance being named in the schedule to the prescription-medicines ordinance ^[31]. British status follows from the regulation that makes injectable medicines prescription-only ^[32].

Australia is the strictest of the seven. The Poisons Standard of June 2026 lists somatropin in schedule 4 and, separately, in Appendix D, clause 5. That clause covers substances a person must not possess without authority, alongside anabolic steroids and the familiar grey-market peptides ^[4].

Research activity is measured rather than absent. The American trial register holds 817 records naming somatropin as an intervention. That count includes unrelated hits and at least one test record that is not a real trial ^[33].

Every entry above reflects the position on 15 September 2026. The wider framework is set out under are peptides legal and FDA-approved peptides.

Anti-doping

Somatropin is banned in sport at all times, in competition and out of it, and it is not caught by a residual clause. It has its own named entry.

The 2026 prohibited list places it in section S2.2.3: "Growth hormone (GH), its analogues and fragments including, but not limited to: growth hormone analogues, e.g. lonapegsomatropin, somapacitan and somatrogon; growth hormone fragments, e.g. AOD-9604 and hGH 176-191" ^[11]. The class heading states that all prohibited substances in it are non-specified substances, which removes the milder sanction band from the table.

German law goes further than sport. The schedule to the Anti-Doping Act names "Somatropin, synonym Wachstumshormon human, Growth Hormone (GH)" word for word, and lists somatrem separately ^[34].

A 2023 ordinance then sets 16 mg of the free compound as the quantity from which possession alone is an offence ^[5]. Australia adds its own possession restriction outside sports law entirely ^[4].

Detection has two routine methods and one longitudinal approach. The isoform test exploits the fact that manufactured material is a single form while the body makes a mixture, but its window is about 12 to 24 hours. The biomarker test reads IGF-1 and a collagen fragment called P-III-NP, lasting one to two weeks but with less specificity.

The underlying difficulty is structural. The hormone that is injected is identical to the one the body makes, the half-life is short, secretion fluctuates, and almost none leaves the body in urine ^[35].

Longitudinal profiling closes part of that gap. Reference distributions come from seven years of anti-doping data on 11,455 elite athletes, validated against a placebo-controlled study in 35 recreational athletes. Tracking IGF-1 and P-III-NP over time can flag misuse ^[36]. More on this class at peptides banned in sport.

Compared with related peptides

Three separations matter here, and the grey market blurs all of them. Somapacitan, somatrogon and lonapegsomatropin are not long-acting versions of somatropin: each has its own name, its own approval and its own code, and the prohibited list calls them analogues rather than the hormone ^[11], ^[13], ^[37]. The releasing factors and secretagogues, among them tesamorelin, cjc-1295, hexarelin and ghrp-2, ask the pituitary gland for more of the body's own hormone instead ^[11].

The fragments are a third thing again. AOD-9604 and hGH 176-191 are pieces of the molecule, and mots-c is unrelated to this axis altogether. The legal contrast is sharper than the chemical one: somatropin is approved everywhere on this page, and none of the fragments or secretagogues is approved anywhere ^[4], ^[11].

Common misconceptions

• "HGH 191AA is a purer or newer substance than the medicine." It is the same substance. Every product approved in the seven markets here is a chain of 191 amino acids in the sequence of the pituitary hormone. The number describes a property all of them share, not a variant ^[2], ^[3].
• "The 192-amino-acid form was a bad fake." It was somatrem, a separate licensed substance with its own code, whose extra methionine came from the bacterial start signal. It is no longer marketed, which makes the distinction correct and obsolete at the same time ^[13], ^[14].
• "Growth hormone makes healthy people stronger." Two independent systematic reviews found no gain in muscle strength and none in maximal oxygen uptake. In one of them, lactate during exercise was higher in two of the three studies that measured it, and swelling and exhaustion were more common ^[7], ^[8].
• "Using it against ageing is merely off-label in the United States." It is a criminal offence. Federal law punishes knowing distribution, or possession with intent to distribute, of growth hormone for any use other than an authorised condition on a doctor's order, with up to five years in prison and ten where a minor is involved ^[6].
• "Grey-market HGH is the pharmacy product at a lower price." Unapproved imported material is refused entry to the United States without physical examination, because falsified products reached the supply chain ^[22]. European enforcement laboratories found growth hormone, sermorelin, melanotan II and samples with no active ingredient at all in seized consignments ^[23]. Even an American pharmacy repackaging an approved product had to recall it in 2015 for lack of assurance of sterility ^[38].
• "Homeopathic HGH sprays and creams contain working hormone." Such products sit in the American listing directory next to the approved injections, some with a potency marking. They are not approved medicines, no efficacy assessment exists, and a 22 kDa protein is not absorbed in useful amounts through the mouth or the skin ^[3], ^[39].
• "Four decades of approval means the long-term safety is settled." The largest cohort, with 24,232 patients and more than 400,000 person-years, shows no raised overall mortality in the low-risk group but raised circulatory and blood-disorder mortality in every group, and its authors call for continued surveillance ^[10], ^[21].
• "A named brand from Asia proves an approval." One Chinese manufacturer's product is licensed in China, but the same company and its chief executive pleaded guilty in an American court in 2010 to unlawfully marketing growth hormone. Two brand names in the American substance register could not be matched to an approval in any of the seven markets here ^[2], ^[40].

Frequently asked questions

Is HGH 191AA the same thing as the medicine somatropin?

Yes. HGH 191AA is a grey-market label for somatropin, the laboratory-made copy of human growth hormone. The number counts the amino acid building blocks in the chain, and every product approved in the United States, the European Union, the United Kingdom, Australia, Canada and Switzerland has exactly those 191. The label describes a property that all licensed products share, not a variant or a quality grade.

What does the 191AA in HGH 191AA actually refer to?

It marks the difference from a 192-amino-acid form sold in the 1980s. That earlier product carried one extra methionine at the front of the chain, left over from the bacterial start signal, and it is a separate licensed substance called somatrem with its own code, H01AC02. Somatrem is no longer marketed, so the distinction is historically correct and has had no practical meaning for decades.

Is somatropin available without a prescription anywhere?

Not in any of the seven markets on this page. It is prescription-only in the United States, the European Union, Germany, the United Kingdom, Canada and Switzerland, where it falls into the strictest Swiss dispensing category. Australia goes further still: the Poisons Standard of June 2026 lists it in Appendix D, clause 5, among the substances a person must not possess without authority.

What is somatropin approved to treat?

Ten distinct conditions across three medical fields, all of them diagnosed by a doctor. In children they are growth failure from insufficient growth hormone, Prader-Willi syndrome, being born small for gestational age without catch-up growth, Turner syndrome, idiopathic short stature, Noonan syndrome and chronic kidney disease. In adults they are growth hormone deficiency, wasting in HIV and short bowel syndrome.

Does HGH 191AA improve athletic performance?

The evidence says it does not. A systematic review of 27 study samples in 303 fit adults found lean body mass higher by 2.1 kg, but no measurable gain in strength or exercise capacity. Lactate during exercise was significantly higher in two of the three studies that measured it, and swelling and exhaustion were more common. A 2017 meta-analysis of 254 healthy young adults found no change in muscle strength or maximal oxygen uptake.

Is somatropin an anti-ageing treatment?

No published evidence supports that use. A systematic review of 220 healthy older adults, average age 69, found fat mass lower by 2.1 kg and lean mass higher by 2.1 kg, with body weight unchanged at plus 0.1 kg. Swelling, joint pain, carpal tunnel syndrome and breast tissue growth in men were all significantly more common. Its authors concluded that growth hormone cannot be advised as an anti-ageing therapy.

Is it legal to use HGH 191AA for bodybuilding in the United States?

No, and this goes beyond off-label use. Federal law makes it an offence to knowingly distribute growth hormone, or to possess it with intent to distribute, for any use other than treating a condition authorised by the health secretary and on a doctor's order. The penalty reaches five years in prison, and ten where a person under 18 is involved. The statute defines growth hormone as somatrem, somatropin or an analogue of either.

Is somatropin banned in sport?

Yes, at all times, in and out of competition. The 2026 prohibited list names growth hormone, its analogues and fragments in its own section, S2.2.3, and classes everything in that class as a non-specified substance. German anti-doping law names somatropin word for word in its schedule, and a separate ordinance sets 16 mg as the quantity from which possession alone is a criminal offence.

How long is somatropin detectable in a doping test?

It depends on the method. The isoform test distinguishes the single form found in manufactured material from the mixture the body makes, but its window is only about 12 to 24 hours after the last administration. The biomarker test, which reads IGF-1 and a collagen fragment called P-III-NP, lasts one to two weeks but is less specific. Longitudinal biomarker profiling extends this further.

What are the main safety concerns with somatropin?

The label rules it out entirely in critical illness after surgery or trauma, in active cancer, and in children with Prader-Willi syndrome who are severely obese or have breathing problems, where sudden deaths have been reported. It can unmask diabetes, raise pressure inside the skull, and cause a slipped growth plate in the hip. In the largest long-term cohort, deaths from circulatory and blood disorders were raised in every risk group.

Cite this page

The facts on this page were checked on 15 September 2026, and the registers behind the status table were queried on that same day. Approved medicines gain new warnings and lose old presentations over time, so the version and the date matter as much as the text.

myPeptides Research & Editing. (2026). Somatropin (HGH 191AA): what the trials show, status and safety. Version 1.0, 15 September 2026. myPeptides Peptide Register. Retrieved from https://mypep.app/peptides/hgh-191aa

How pages in this register are compiled and graded is described under methodology; the full register is at peptides.

Last verified: 15 September 2026. Next review: on a labelling change in the United States, on a new authorisation or withdrawal in any of the seven markets, or on any change in the anti-doping classification.