Somatropin (growth hormone): approved uses, research, side effects and status in Finland

In short

Somatropin is a hormone made in bacteria that is identical to human growth hormone, and in the EU it is a prescription medicine with a marketing authorisation for growth disorders and severe growth hormone deficiency in adults [1]regulator [2]official. In healthy young people it increased lean body mass but not muscle strength or endurance [9, 10]A.

• In treatment, somatropin is used for growth disorders in children, such as growth hormone deficiency and Turner syndrome, and for severe growth hormone deficiency in adults [2]official.
• In healthy young people, a review of 27 study samples found that lean body mass increased but strength and exercise capacity did not improve, and swelling and fatigue were more common [9]A. In a trial of 96 recreational athletes only sprint capacity improved, and the gain was gone six weeks after stopping [11]A.
• The clearest warning comes from intensive care: in two randomised trials, mortality was clearly higher with growth hormone than with placebo (39% vs 20% and 44% vs 18%) [15]A. In older people, swelling, joint pain and carpal tunnel symptoms were more common [12, 13]A.
• In Finland somatropin is on the medicines list and has authorised products [3, 4]regulator. Growth hormone is a doping substance under the Finnish Criminal Code [5]regulator, and WADA prohibits it in sport at all times [7]regulator.

What is somatropin?

Somatropin is growth hormone used as a medicine. According to the EMA it is identical to the body's own growth hormone, which is released by the pituitary gland and is important for growth during childhood and adolescence [1]regulator. The medicine is made with recombinant DNA technology: bacteria produce the hormone after a gene for it has been introduced into them [1]regulator. According to the product information, the bacterium used is Escherichia coli [2]official.

Growth hormone is a peptide hormone. According to a review, the pituitary releases it in pulses as several different forms, whereas recombinant growth hormone is a single pure form (22 kDa) [21]. A doping test is based on this difference (see Is somatropin doping?).

Somatropin is a medicine in Finland: it is in annex 1 of Fimea's medicines list [4]regulator. Growth hormone is also a doping substance under the Finnish Criminal Code [5]regulator. Peptide basics: What are peptides?. All substances: Peptides A-Z.

Evidence at a glance

Each cell gives the kind of study and its source. The letter is the evidence level, not the result.

"-" = animal and cell studies are not covered on this page, because human studies are plentiful.

What is somatropin used for?

Somatropin is used to treat growth disorders and growth hormone deficiency. The approved indications in the product information are [2]official:

• Children and adolescents: growth disturbance due to insufficient secretion of growth hormone; growth disturbance associated with Turner syndrome; growth disturbance associated with chronic renal insufficiency; growth disturbance in children born small for gestational age who have not caught up by four years of age; and Prader-Willi syndrome, to improve growth and body composition [2]official.
• Adults: replacement therapy in pronounced growth hormone deficiency. The deficiency may start in adulthood or continue from childhood, and it must be confirmed by testing before treatment [1]regulator [2]official.

According to the EMA, the medicine is available only on prescription, and treatment is started and monitored by a doctor experienced in managing growth disorders. It is injected under the skin, and the patient or a caregiver can inject it after training. The doctor calculates the dose for each patient individually according to body weight and the condition being treated [1]regulator.

Not an approved use. Building muscle, athletic performance and slowing ageing are not approved indications [2]official. According to a review, growth hormone is widely used as an anti-ageing therapy, although the US Food and Drug Administration has not approved it for this [12]A.

How does somatropin work?

Somatropin affects the metabolism of fats, carbohydrates and proteins. According to the product information it speeds up growth in children who lack growth hormone, and in both children and adults it maintains body composition: it increases nitrogen retention, skeletal muscle growth and the breakdown of fat. Abdominal (visceral) fat is particularly responsive [2]official.

According to the product information, somatropin raises blood levels of IGF-1 (insulin-like growth factor 1) and its binding protein IGFBP3. It increases liver LDL cholesterol receptors, raises insulin, quickly increases plasma and extracellular fluid volume, and retains sodium, potassium and phosphorus [2]official. Fluid retention explains some of the side effects (see side effects).

In healthy young people, two weeks of growth hormone increased collagen synthesis in tendon and muscle, but not the synthesis of the muscle cells' contractile protein. The authors concluded that growth hormone strengthens the supporting tissue more than it grows muscle cells [25]B.

Has somatropin been studied in humans?

Yes, extensively. For treatment use there are randomised, placebo-controlled trials and meta-analyses [19, 20]A, and follow-up studies of tens of thousands of patients [17, 18]B. In healthy young and older people there are randomised trials and reviews of them [9, 10, 11, 12]A.

Treatment use

• Children with growth hormone deficiency. According to the EPAR, Omnitrope (somatropin) was compared with Genotropin (somatropin) in 89 children who lacked growth hormone. After nine months, children in both groups grew about 10.7 cm per year [1]regulator.
• Short children without deficiency. In a review of three randomised trials (115 children), adult height of treated children was on average about 4 cm greater than in controls. The effect was smaller than in the approved indications, and individual response varied widely [20]A.
• Growth hormone deficiency in adults. In a meta-analysis of 37 blinded placebo-controlled trials, treatment lowered LDL and total cholesterol, fat mass and diastolic blood pressure and increased lean body mass, but raised fasting blood glucose and insulin. According to the authors, the overall benefit for the heart still has to be shown in large trials [19]A.

Healthy young people and athletes

• Review 2008. In 27 study samples, 303 healthy, fit young people received growth hormone, on average for about three weeks. Lean body mass increased by an average of 2.1 kg, but strength and exercise capacity did not seem to improve. Swelling and fatigue were more common. According to the authors, claims of improved performance are not supported by the scientific literature [9]A.
• Meta-analysis 2017. In 11 studies (254 people), growth hormone increased lean body mass and reduced fat, but over weeks to months it did not improve muscle strength or maximum oxygen uptake. Anaerobic capacity improved in the only study that measured it [10]A.
• Recreational athletes 2010. 96 recreational athletes (63 men, 33 women) received growth hormone, testosterone, both or placebo for eight weeks. Growth hormone reduced fat and increased lean mass mainly through extracellular fluid. Sprint capacity improved by 3.9%, but strength, jump power and endurance did not change, and the sprint gain was gone within six weeks of stopping [11]A.
• Resistance training 1992. 16 young men did 12 weeks of resistance training with growth hormone or placebo. Lean mass grew more with growth hormone, but muscle protein synthesis, limb circumferences and strength increased equally in both groups. According to the authors, the extra mass was probably not skeletal muscle [23]A.

Older people

• 1990. In a study of 21 men over 60, the 12 men who received growth hormone gained 8.8% lean body mass and lost 14.4% adipose tissue in six months [14]B. The study was small and not randomised.
• Review 2007. In 18 study populations, 220 healthy older people received growth hormone. Fat mass fell and lean mass rose by about 2 kg each, but weight and bone density did not change. Swelling, joint pain, carpal tunnel syndrome and breast enlargement in men were more common, and diabetes slightly more common. According to the authors, growth hormone cannot be recommended as an anti-ageing therapy [12]A.
• Growth hormone and sex hormones 2002. 131 older women and men received growth hormone, sex hormones, both or placebo for six months. Lean body mass increased, but strength did not increase significantly except in men on the combination, and that only marginally. Diabetes or impaired glucose tolerance occurred in 18 men on growth hormone and 7 without it [13]A.
• Resistance training 2002. In 31 healthy older men, growth hormone alone or with resistance training did not increase thigh muscle strength or size more than training without it. Many side effects were reported [24]A.

Who studies somatropin?

The long-term safety of somatropin is followed by the European SAGhE consortium in eight countries (Belgium, France, Germany, Italy, the Netherlands, Sweden, Switzerland and the UK), funded by the European Union [17]B. The recreational athlete trial was done at the Garvan Institute in Sydney and funded by the World Anti-Doping Agency WADA [11]A. Of the intensive care trials, one included 247 Finnish patients and the other 285 patients in other European countries [15]A.

The same US researchers wrote systematic reviews of trials in healthy young and older people [9, 12]A, and there is a recent broad review of growth hormone doping and its detection [21].

Author of this page: editorial team

This page was written by the Molecular Recovery editorial team. The draft was produced with AI assistance, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.

How long does somatropin stay in the body?

Somatropin leaves the blood quickly. According to the product information its half-life after injection into a vein is about 0.4 hours in adults, but about 3 hours after injection under the skin, because the hormone is absorbed slowly from the injection site [2]official.

About 80% of somatropin injected under the skin reaches the circulation in both healthy people and people with growth hormone deficiency, and in healthy adults the peak level was reached in about four hours. Information on older people, children and people with kidney, liver or heart disease is incomplete [2]official.

According to a review, the body releases growth hormone in pulses, and it is cleared from the blood quickly [21].

What are the side effects of somatropin?

The most common side effects of somatropin come from fluid retention, and more serious harms have also been described. According to the product information, swelling and joint pain are very common in adults and usually appear in the first months of treatment [2]official. More: Side effects and safety.

Side effects in the product information

• Fluid retention: swelling of the limbs and joint pain are very common; muscle stiffness, muscle pain and pins and needles are common. They are usually mild to moderate and go away by themselves or with a lower dose [2]official. According to the EPAR they are uncommon in children [1]regulator.
• Blood sugar: somatropin may reduce insulin sensitivity, and type 2 diabetes is a listed adverse reaction. A diabetic patient's insulin dose may need adjusting [2]official.
• Others: carpal tunnel syndrome, headache, rash, breast enlargement in men, underactive thyroid and lower cortisol. Raised pressure inside the skull is possible; it is suspected if severe headache, visual problems, nausea or vomiting occur [2]official.
• Children: slipped capital femoral epiphysis and Legg-Calvé-Perthes disease have been reported, pancreatitis rarely, and progression of scoliosis is monitored. Deaths have been reported in children with Prader-Willi syndrome who had severe obesity, breathing problems or sleep apnoea as a risk factor [2]official.
• Tumours: in childhood cancer survivors, an increased risk of a second tumour has been reported after growth hormone treatment, most often meningiomas in those who had radiation to the head. Leukaemia has been reported in a small number of patients who received growth hormone, but there is no evidence of a raised risk without predisposing factors [2]official.

Intensive care patients

In two randomised trials (532 intensive care patients), high-dose growth hormone raised in-hospital mortality: 39% vs 20% with placebo in the Finnish trial and 44% vs 18% in the multinational trial. Among survivors, intensive care and mechanical ventilation lasted longer [15]A. For this reason the product information prohibits somatropin in acute critical illness, for example complications after heart or abdominal surgery or multiple trauma [2]official.

Long-term follow-up after childhood treatment

In a French follow-up of 6,928 patients, all-cause mortality was raised, especially in those on the highest doses, and deaths related to bone tumours and brain haemorrhage were more common [16]B. In the eight-country SAGhE data on 24,232 patients, mortality was not raised in those with isolated growth hormone deficiency or short stature without another cause, and it was not related to dose. Deaths from circulatory and blood diseases were, however, more common in all risk groups [17]B.

In the same data, cancer risk was not generally raised in patients who only had a growth disorder. Bone and bladder cancers were more common in those without previous cancer, and Hodgkin lymphoma incidence rose with longer follow-up; the authors say these need further study [18]B.

Healthy people and athletes

In healthy young people growth hormone increased swelling and fatigue [9]A. According to its authors, the recreational athlete trial was too small to judge safety [11]A. In older people adverse effects were so frequent, especially diabetes and impaired glucose tolerance, that the authors would confine use to controlled studies [13]A.

Interactions and who lacks data

According to the product information, glucocorticoids (cortisone medicines) weaken the growth-promoting effect of somatropin, and somatropin can unmask hidden adrenal insufficiency or make replacement therapy less effective. Oestrogen taken by mouth can increase the need for somatropin [2]official.

Somatropin may speed up the clearance of medicines removed through the CYP3A4 enzyme, such as sex steroids, corticosteroids, anticonvulsants and ciclosporin. The clinical significance of this is unknown [2]official.

Somatropin must not be used when there are signs of an active tumour, in acute life-threatening illness, or to promote growth once the growth plates of the bones have closed. Experience in people over 80 is limited, and there is limited information on long-term treatment in adults and in Prader-Willi syndrome [2]official.

Evidence against and what we do not know

In treatment use the benefit of somatropin was accepted as the basis of its marketing authorisation [1]regulator, but in healthy adults most studies do not support claims of more strength, endurance or rejuvenation [9, 10, 12]A.

Contrary evidence

• In two reviews, strength and maximum oxygen uptake did not improve in healthy young people [9, 10]A.
• Resistance training with growth hormone did not build more muscle or strength than training without it, in young men [23]A or older men [24]A.
• The gain in lean mass in recreational athletes was mostly extracellular fluid [11]A.
• In intensive care patients growth hormone increased mortality, although it was hoped to reduce the tissue breakdown caused by illness [15]A.
• Mortality was raised in the French data [16]B but not in low-risk patients in the full SAGhE data [17]B: the results partly conflict.

What the evidence does not support

• "Growth hormone builds muscle": lean mass increases, but muscle protein synthesis and strength did not rise more than with training alone [23]A [25]B [9]A.
• "Growth hormone improves endurance": maximum oxygen uptake did not rise [10]A, and according to a review exercise capacity may even get worse [9]A.
• "Growth hormone slows ageing": in older people the changes were small and adverse effects more common; according to a review it cannot be recommended as an anti-ageing therapy [12]A.
• "Growth hormone strengthens older people's bones": in a small study of 21 men lumbar spine bone density rose by 1.6% [14]B, but in a review of randomised trials bone density did not change [12]A.

What is not known

• Whether the amounts athletes use act differently from those in trials. The authors of the recreational athlete trial say the dose may have been lower than competitive athletes use covertly, and the athletic significance of the sprint gain is unclear [11]A.
• Long-term safety in healthy adults: the reviewed studies lasted on average weeks or months [9, 12]A.
• Why circulatory deaths were more common after childhood treatment. According to the authors, surveillance is still needed [17]B.
• Whether treating adult growth hormone deficiency has an overall benefit for the heart; according to the meta-analysis this needs large trials [19]A.

Somatropin dosing

Somatropin is a prescription medicine, so this site has no dose page or calculator for it. The treating doctor decides the dose according to the product's approved information [2]official.

According to the EMA, the doctor calculates the dose for each patient individually according to body weight and the condition being treated, and the dose may need adjusting with changes in weight and response [1]regulator. According to the product information, the maximum recommended daily dose should not be exceeded [2]official.

What the studies cannot tell you. The amounts given to healthy people in trials were chosen for the study design and are not recommendations. According to the product information, side effects such as swelling are related to dose [2]official, and in the intensive care trials high doses were associated with higher mortality [15]A.

Somatropin vs growth hormone-releasing substances: what is the difference?

Somatropin is growth hormone itself. The substances in section S2.2.4 of the WADA list are growth hormone-releasing factors instead. WADA classifies them separately but prohibits both [7]regulator:

• Growth hormone, its analogues and fragments (S2.2.3): somatropin, the long-acting analogues (lonapegsomatropin, somapacitan, somatrogon) and fragments such as AOD-9604 [7]regulator.
• Growth hormone-releasing factors (S2.2.4): the GHRH-like CJC-1295, sermorelin and tesamorelin; the secretagogues ipamorelin and MK-677 (ibutamoren); and hexarelin, GHRP-2 and GHRP-6 [7]regulator.
• Growth factors (S2.3): IGF-1 and its analogues, such as IGF-1 LR3, and MGF [7]regulator.

The difference for the reader: somatropin has authorised products in the EU and Finland [3]regulator, whose quality and side effects are described in the product information [2]official. The pages of the growth hormone-releasing substances describe their own evidence. On blends: CJC-1295 + ipamorelin.

Combinations: growth hormone and testosterone

According to the authors of the recreational athlete trial, athletes use growth hormone widely and often together with androgenic steroids [11]A. In a survey of 231 experienced young male weightlifters, 27 (12%) reported using growth hormone or IGF-1; all of them had also used anabolic steroids [22]B.

The combination has been studied in two randomised trials. In recreational athletes, sprint capacity improved by 8.3% with growth hormone plus testosterone, but other performance measures did not change [11]A. In older men the combination increased lean mass the most, but the gain in strength was marginal, and carpal tunnel symptoms occurred in 32% of those on the combination but in no one on placebo [13]A.

We found no other combinations in controlled human studies. Legal matters in general: Peptides and the law in Finland.

Is somatropin legal in Finland?

In Finland somatropin is a prescription medicine and a doping substance under the Criminal Code. It is in annex 1 of the medicines list [4]regulator, and according to the EMA it is available only on prescription [1]regulator.

• Marketing authorisations. In the EMA Article 57 data (as of 9 Oct 2026), Genotropin (somatropin), Norditropin FlexPro (somatropin) and Saizen (somatropin) have a Finnish national authorisation, and Omnitrope (somatropin) and Skytrofa (lonapegsomatropin) an EU-wide authorisation. All are given under the skin [3]regulator. Article 57 shows the authorisation, not whether the product is available in pharmacies.
• Doping substance. Government Decree 705/2002 lists, as doping substances under chapter 44 of the Criminal Code, "kasvuhormoni" (growth hormone) and substances that increase growth hormone production in the human body, such as IGF-1 [5]regulator.
• Wording of the Criminal Code. Under chapter 44, section 6 (doping offence), it is punishable if a person unlawfully ("laittomasti") does any of the following: "valmistaa tai yrittää valmistaa dopingainetta" (manufacture or attempt to manufacture a doping substance), "tuo tai yrittää tuoda maahan dopingainetta" (import or attempt to import a doping substance) or "myy, välittää, toiselle luovuttaa tai muulla tavoin levittää tai yrittää levittää dopingainetta" (sell, broker, hand over or otherwise distribute, or attempt to distribute, a doping substance), and the penalty is "sakkoon tai vankeuteen enintään kahdeksi vuodeksi" (a fine or imprisonment for at most two years) [6]regulator.
• Travel and import. General information: Peptides and the law in Finland and Travelling with peptides.

This is not legal advice. Disclaimer.

Is somatropin doping?

Yes. On WADA's 2026 Prohibited List, growth hormone, its analogues and fragments are in class S2.2.3, and substances in class S2 are prohibited at all times, in and out of competition [7]regulator. On the Finnish-language list of SUEK, growth hormone (GH, somatotropin) with its analogues and fragments is in the same section S2.2.3 [8]regulator.

According to a review, growth hormone doping probably began in the early 1980s. Two validated methods detect it: the isoform test distinguishes recombinant hormone from the forms released by the pituitary, and the marker test measures blood proteins raised by growth hormone (IGF-1 and the collagen marker P-III-NP). Since 2004 only a handful of athletes have been caught, which according to the review reflects the limits of testing [21].

Athletes can check the status of substances in the list of the Finnish Center for Integrity in Sports SUEK [8]regulator.

How is the quality of a somatropin product assessed?

The quality of authorised somatropin is assessed as part of the marketing authorisation. For example, Omnitrope (somatropin) is a biosimilar that the EMA found comparable in quality, safety and effectiveness to the reference medicine [1]regulator.

According to the product information, the name and batch number of a biological medicine are recorded for traceability [2]official, and according to the EMA, cartridges of Omnitrope (somatropin) are used only with the product's own injection device [1]regulator. Antibodies develop in about 1% of patients, but they did not affect growth [2]official.

We did not assess analyses of the content of unauthorised products for this page. A certificate of analysis (COA) does not show a product to be safe. More: How to read a COA and check a test result.

The future: what comes next?

Long-acting products given once a week have appeared alongside somatropin. Besides somatropin, the medicines list includes the long-acting lonapegsomatropin, somapacitan and somatrogon [4]regulator, and Skytrofa (lonapegsomatropin) has an EU marketing authorisation [3]regulator. In a 2026 meta-analysis (30 studies, 3,287 children), once-weekly growth hormone gave the same growth as daily treatment, raised IGF-1 more, and the overall rate of adverse events was similar. According to the authors, long-term studies are needed [26]A.

Follow-up of the long-term safety of childhood treatment continues: according to the SAGhE researchers, the excess of certain causes of death still needs surveillance [17]B, and the individual cancer findings need further study [18]B.

FAQ

Read the research yourself: sources

Every source opens the original publication or the regulator's page. The level shows what the source itself reports.

1. European Medicines Agency. Omnitrope (somatropin): EPAR summary and authorisation details (marketing authorisation issued 12 Apr 2006). EMA regulator
2. European Medicines Agency. Omnitrope (somatropin): EPAR product information, Annex I summary of product characteristics. Last updated 5 Aug 2025. EMA (PDF) official
3. European Medicines Agency. Article 57 product data (EMA/518502/2018, data as of 9 Oct 2026): somatropin entries for Finland and the European Union. EMA regulator
4. Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1: somatropin, lonapegsomatropin, somapacitan, somatrogon. Finlex regulator
5. Finland. Government Decree on doping substances referred to in chapter 44, section 16 of the Criminal Code (705/2002), section 1: growth hormone. Finlex regulator
6. Finland. Criminal Code (39/1889), chapter 44, section 6: doping offence. Finlex regulator
7. World Anti-Doping Agency. 2026 Prohibited List, S2.2.3 Growth hormone (GH), its analogues and fragments. wada-ama.org (PDF) regulator
8. Finnish Center for Integrity in Sports (SUEK). Doping substance groups and substances 2026, based on the WADA list: S2.2.3. SUEK regulator
9. Liu H, Bravata DM, Olkin I, et al. Systematic review: the effects of growth hormone on athletic performance. Ann Intern Med. 2008;148(10):747-758. PMID 18347346 A
10. Hermansen K, Bengtsen M, Kjær M, Vestergaard P, Jørgensen JOL. Impact of GH administration on athletic performance in healthy young adults: A systematic review and meta-analysis of placebo-controlled trials. Growth Horm IGF Res. 2017;34:38-44. PMID 28514721 A
11. Meinhardt U, Nelson AE, Hansen JL, et al. The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial. Ann Intern Med. 2010;152(9):568-577. PMID 20439575 A
12. Liu H, Bravata DM, Olkin I, et al. Systematic review: the safety and efficacy of growth hormone in the healthy elderly. Ann Intern Med. 2007;146(2):104-115. PMID 17227934 A
13. Blackman MR, Sorkin JD, Münzer T, et al. Growth hormone and sex steroid administration in healthy aged women and men: a randomized controlled trial. JAMA. 2002;288(18):2282-2292. PMID 12425705 A
14. Rudman D, Feller AG, Nagraj HS, et al. Effects of human growth hormone in men over 60 years old. N Engl J Med. 1990;323(1):1-6. PMID 2355952 B
15. Takala J, Ruokonen E, Webster NR, et al. Increased mortality associated with growth hormone treatment in critically ill adults. N Engl J Med. 1999;341(11):785-792. PMID 10477776 A
16. Carel JC, Ecosse E, Landier F, et al. 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. 2012;97(2):416-425. PMID 22238382 B
17. Sävendahl L, Cooke R, Tidblad A, et al. Long-term mortality after childhood growth hormone treatment: the SAGhE cohort study. Lancet Diabetes Endocrinol. 2020;8(8):683-692. PMID 32707116 B
18. Swerdlow AJ, Cooke R, Beckers D, et al. Cancer Risks in Patients Treated With Growth Hormone in Childhood: The SAGhE European Cohort Study. J Clin Endocrinol Metab. 2017;102(5):1661-1672. PMID 28187225 B
19. Maison P, Griffin S, Nicoue-Beglah M, et al. Impact of growth hormone (GH) treatment on cardiovascular risk factors in GH-deficient adults: a Metaanalysis of Blinded, Randomized, Placebo-Controlled Trials. J Clin Endocrinol Metab. 2004;89(5):2192-2199. PMID 15126541 A
20. Deodati A, Cianfarani S. Impact of growth hormone therapy on adult height of children with idiopathic short stature: systematic review. BMJ. 2011;342:c7157. PMID 21398350 A
21. Holt RIG, Ho KKY. The Use and Abuse of Growth Hormone in Sports. Endocr Rev. 2019;40(4):1163-1185. PMID 31180479 (review)
22. Brennan BP, Kanayama G, Hudson JI, Pope HG Jr. Human growth hormone abuse in male weightlifters. Am J Addict. 2011;20(1):9-13. PMID 21175915 B
23. Yarasheski KE, Campbell JA, Smith K, Rennie MJ, Holloszy JO, Bier DM. Effect of growth hormone and resistance exercise on muscle growth in young men. Am J Physiol. 1992;262(3 Pt 1):E261-E267. PMID 1550219 A
24. Lange KH, Andersen JL, Beyer N, et al. GH administration changes myosin heavy chain isoforms in skeletal muscle but does not augment muscle strength or hypertrophy, either alone or combined with resistance exercise training in healthy elderly men. J Clin Endocrinol Metab. 2002;87(2):513-523. PMID 11836279 A
25. Doessing S, Heinemeier KM, Holm L, et al. Growth hormone stimulates the collagen synthesis in human tendon and skeletal muscle without affecting myofibrillar protein synthesis. J Physiol. 2010;588(Pt 2):341-351. PMID 19933753 B
26. Liu F, Xiu L, Zhang W, Zang C, Wang S. Weekly long-acting growth hormone versus daily growth hormone therapy on quality of life, efficacy, and safety in children with short stature: a systematic review and meta-analysis. Front Endocrinol (Lausanne). 2026;17:1907184. PMID 42751562 A

Research sources (PubMed) and regulatory sources (EMA, Finlex, WADA, SUEK) read on 15 Oct 2026.

Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.

Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.