Human Growth Hormone (HGH, Somatropin)
PharmaceuticalThe medical_score (82) is 14 points above the community_score (68), as the medical evidence primarily reflects the well-established GHD treatment [s4, s5, s6], whereas community reports frequently reflect off-label scenarios in which the benefit-risk balance is less favorable and counterfeits as well as high costs negatively influence user experiences [c1, c2, c3].
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TL;DR
Somatropin is well-supported by multiple RCTs and systematic reviews for genuine growth hormone deficiency (GHD), with consistent improvements in body composition, bone density, and quality of life. For anti-aging and athletic performance, convincing RCT data are absent, while long-term risks including insulin resistance and a potentially elevated cancer risk are real and not negligible. The community consistently overestimates muscle-building effects without concurrent anabolics — fat loss and recovery are the more realistic outcomes. Possession without a prescription is a criminal offense in Germany, and black-market products are frequently counterfeit.
Description
Prescription recombinant growth hormone for treatment of growth hormone deficiency; significant safety risks outside approved indications [s1, s2].
Somatropin is a recombinantly engineered recombinant human growth hormone (rhGH) structurally identical to endogenous pituitary growth hormone [s1]. It was first approved in the USA in 1985 for the treatment of children with growth hormone deficiency (GHD) and has since been extended to numerous additional indications, including Turner syndrome, Prader-Willi syndrome, chronic renal insufficiency in children, short stature in SGA children, adult GHD, HIV-associated wasting syndrome, and short bowel syndrome [s1, s2]. The medical evidence for use in confirmed GHD is well established: in this population, rhGH improves body composition (increased lean mass, reduced fat mass), increases bone density, and improves lipid profile and quality of life [s4, s5]. In children with GHD, enhancement of linear growth is well documented [s6]. In the off-label setting—particularly anti-aging and bodybuilding—somatropin is widely used, although evidence for these applications is considerably weaker [s7, s8]. A systematic review of GH and athletic performance showed no significant improvement in maximal strength or VO₂max, but an increase in body weight due to water retention [s8]. Anti-aging studies demonstrated changes in body composition but no clinically meaningful functional improvements in healthy older individuals, while adverse effects were frequent [s7]. Counterfeit and adulterated products are widespread on the German black market, substantially increasing risk [s3]. Somatropin is a prohibited doping substance under the AntiDopG [s3].
Legal Status (DE)
In Germany, somatropin is a prescription-only medicinal product (Rx), approved for defined indications (growth hormone deficiency, Turner syndrome, Prader-Willi syndrome, chronic renal insufficiency, SGA, short bowel syndrome, and others) [s1, s2]. Any use outside these indications constitutes off-label use. Use for doping purposes is a criminal offense under the Anti-Doping Act (AntiDopG); possession without a prescription violates the Medicinal Products Act (AMG) [s3]. Somatropin is listed in Annex 1 of the AntiDopG [s3].
Mechanism of Action
Somatropin binds to the membrane-bound growth hormone receptor (GHR), which belongs to the cytokine receptor family. Binding induces receptor dimerization and activates the associated tyrosine kinase JAK2 (Janus kinase 2) [s9, s10]. JAK2 phosphorylates STAT5b (Signal Transducer and Activator of Transcription 5b), which as a transcription factor directly stimulates IGF-1 gene expression in hepatocytes [s9, s10]. IGF-1 (Insulin-like Growth Factor 1) is the principal mediator of the growth-promoting effects of GH in peripheral tissues [s10, s11]. Additionally, GHR activates the following signaling pathways [s9]: - MAPK/ERK pathway: mediates cell proliferation - PI3K/Akt pathway: mediates metabolic effects and cell survival - STAT1/STAT3 pathways: additional transcriptional effects Direct metabolic effects of GH include [s12, s13]: - Lipolysis in adipocytes (direct GH effect, opposing IGF-1 action) - Gluconeogenesis and inhibition of glucose uptake (diabetogenic effect, acute insulin resistance) - Stimulation of protein synthesis in skeletal muscle GH significantly suppresses myostatin mRNA expression in skeletal muscle (to 31 ± 9% of control value, p<0.001), considered one mechanism of its anabolic action [s14]. GH prevents the protein-catabolic effect of glucocorticoids by increasing protein synthesis without inhibiting proteolysis [s15]. GH-induced insulin resistance is acute and reversible, resolving within 5 hours after cessation of GH exposure [s16]. Circadian administration of somatropin in the evening more closely mimics the physiological nocturnal GH secretion pattern than morning administration and results in more favorable hormone and metabolite profiles [s17].
Dosing
Allgemein
- Dose
- Up to 0.054 mg/kg/day (equivalent to up to 0.375 mg/kg/week)
- Frequency
- Täglich
- Route
- injektion-subkutan
- Duration
- Bis zum Epiphysenschluss; Behandlungsdauer individuell
- With food
- optional
Allgemein
- Dose
- 0.24 mg/kg/week (equivalent to approx. 0.034 mg/kg/day)
- Frequency
- Täglich (6–7 Injektionen/Woche)
- Route
- injektion-subkutan
- Duration
- Individuell; Überprüfung der Indikation bei Erwachsenwerden
- With food
- optional
Allgemein
- Dose
- Up to 0.067 mg/kg/day (equivalent to up to 0.47 mg/kg/week)
- Frequency
- Täglich
- Route
- injektion-subkutan
- Duration
- Bis zum Aufholwachstum oder Epiphysenschluss; Therapiebeginn ab 2–4 Jahren bei fehlendem Aufholwachstum
- With food
- optional
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Wasserretention / periphere Ödeme GH-induced sodium and water retention; occurs particularly at treatment initiation and often diminishes over time [s1, s21]. | häufig | leicht |
| Gelenkschmerzen (Arthralgien) und Myalgien Direct effect of GH action on joints and soft tissues; dose-dependent [s21]. | häufig | leicht |
| Karpaltunnelsyndrom (Parästhesien, Taubheitsgefühl der Hände) Common side effect (paresthesia 17.3%, hypoesthesia 15%), presumably caused by tissue edema [s21]. | häufig | moderat |
| Insulinresistenz / Hyperglykämie GH inhibits insulin-mediated glucose uptake (SOCS3 upregulation); acutely reversible after approximately 5 hours, persistent with long-term administration [s16, s21]. | häufig | moderat |
| Benigne intrakranielle Hypertension (Pseudotumor cerebri) Particularly in children; symptoms: headache, visual disturbances, papilledema. Treatment discontinuation required [s20, s21]. | selten | schwer |
| Akromegalie-ähnliche Veränderungen (Vergröberung der Gesichtszüge, Organvergrößerung) At supraphysiological doses (overdose) or long-term use outside approved indications [s21]. | selten | schwer |
| Hypothyreose (sekundäre Schilddrüsenunterfunktion) GH can alter thyroid hormone metabolism; regular monitoring recommended [s20]. | gelegentlich | moderat |
| Gynäkomastie Reported with long-term use, possibly via IGF-1-mediated estrogen stimulation [s21]. | selten | leicht |
| Erhöhtes Krebsrisiko (Zweittumoren bei vorbehandelten Patienten) Meta-analysis showed increased cancer risk (SIR 2.74; 95% CI 1.18–4.41) and increased risk of second malignancies (RR 1.99; 95% CI 1.28–3.08) in pediatric studies, particularly in high-risk groups [s18]. No significantly elevated risk in low-risk groups (isolated GHD, ISS, SGA) in more recent large cohorts [s18]. | selten | schwer |
| Diabetes mellitus (Manifestation oder Verschlechterung) GH can unmask latent diabetes or worsen pre-existing diabetes [s21]. | gelegentlich | moderat |
| Epiphysenlösung (Slipped Capital Femoral Epiphysis) bei Kindern Known pediatric adverse effect; hip pain requires immediate evaluation [s20]. | selten | schwer |
Contraindications
IGF-1 has mitogenic and anti-apoptotic effects; GH must not be used in active or untreated tumors [s18, s1].
GH-induced IGF-1 elevation may worsen proliferative retinopathy [s1].
Increased mortality under high-dose GH administration in critically ill patients was observed in clinical trials [s1].
Sudden deaths during GH therapy have been reported in PWS patients with respiratory problems [s1].
No further growth response possible; acromegaloid effects may occur [s20].
Insufficient safety data available; use is contraindicated [s1].
GH worsens insulin resistance; glycemic control must be optimized prior to initiating therapy [s16, s21].
Interactions
Synergistic
Ipamorelin stimulates GH release via the GHRP receptor (GHS-R), while exogenous somatropin directly raises GH levels. The combination may act synergistically, with Ipamorelin supporting pulsatile secretion and somatropin elevating baseline levels.
As a GHRH analogue, CJC-1295 stimulates the pituitary to increase GH production. In combination with exogenous somatropin, the overall effect on IGF-1 levels and anabolic processes may be enhanced.
As a short-acting GHRH analogue, CJC-1295 without DAC supplements GH pulses and may synergistically increase IGF-1 production and tissue-anabolic effects in combination with exogenous somatropin.
BPC-157 increases growth hormone receptor density in tendon cells and upregulates tissue-regenerative transcription factors. In combination with somatropin, this may enhance healing and regenerative effects.
Ashwagandha lowers cortisol levels via HPA axis modulation. Since elevated cortisol inhibits GH secretion, Ashwagandha may indirectly improve the GH/IGF-1 environment of exogenous somatropin.
GHRP-2 stimulates pulsatile GH release from the pituitary via the GHS-R1a receptor. In combination with exogenous somatropin, both substances may synergistically activate the GH/IGF-1 axis, with GHRP-2 supplementing endogenous secretion.
GHRP-6 is a potent GH secretagogue that stimulates GH release via the ghrelin receptor. Combination with exogenous somatropin may enhance the overall effect on IGF-1 and muscle anabolic processes.
Arginine is a known secretion stimulus for somatropin via inhibition of somatostatin release. Arginine supplementation can promote endogenous GH secretion, thereby complementing the effects of exogenous somatropin.
TB-500 promotes tissue regeneration via actin polymerization and angiogenesis through a different signaling pathway than somatropin. The combination of both substances may exert complementary effects on tissue healing and regeneration.
Caution
Antiepileptics can modulate the GH-IGF-1 axis via neuroendocrine mechanisms (blockade of voltage-gated Na⁺/Ca²⁺ channels, modulation of GHRH secretion) as well as through induction or inhibition of CYP450 isoenzymes. Clinical data show no consistent picture: in pediatric cohorts, elevated IGF-1 levels were measured in some cases under carbamazepine/oxcarbazepine; a clinically sign...
Somatropin causes dose-dependent insulin resistance and elevated blood glucose levels. Berberine improves insulin sensitivity and influences the IGF signaling pathway. The combination may attenuate or unpredictably modulate the glucose metabolism-related effects of somatropin.
Alpha-lipoic acid improves insulin sensitivity and mitochondrial glucose utilization. Since somatropin increases insulin resistance, alpha-lipoic acid may partially compensate for GH-induced glucose metabolism disturbances – the combination is not fundamentally problematic but should be accompanied by blood glucose monitoring.
Both somatropin and DHEA simultaneously influence multiple hormonal systems (sex hormones, insulin sensitivity, IGF-1). Combined use may lead to an uncontrolled summation of hormonal effects that is difficult to predict.
Ashwagandha can increase thyroid hormones (T3/T4), particularly in hypothyroidism. Since somatropin therapy itself can affect thyroid function (TSH suppression, induction of hypothyroidism), there is a risk of unpredictable thyroid effects with concomitant use.
Somatropin inhibits insulin-stimulated peripheral glucose uptake and increases hepatic gluconeogenesis, which can lead to hyperglycemia. Concomitant insulin administration carries the risk of uncontrolled blood glucose fluctuations and severe hypoglycemia in the event of dosing errors.
Somatropin influences the metabolism of sex hormones via CYP3A4 induction and can indirectly modulate the HPG axis. Concomitant use with gonadorelin, which stimulates LH/FSH secretion, may lead to unpredictable hormonal feedback effects.
Enclomiphene increases endogenous testosterone and IGF-1 production via blockade of estrogen receptors at the hypothalamus. In combination with somatropin, the anabolic and metabolic effects on insulin sensitivity and hormone levels may accumulate in an uncontrolled manner.
Studies
Tier B — Moderate Evidence
Outcome: Long-term safety of GH replacement therapy in adults with GHD: mortality, malignancies, cardiovascular events, tumor recurrence
Effect Size: Mortality 3.8%; most common causes of death: malignancies, cardiovascular disease, infections, cerebrovascular disease; no increased de novo malignancy rate under GH replacement
Outcome: Prevalence and incidence of diabetes mellitus under GH replacement therapy in adult GHD patients
Effect Size: DM prevalence 8.2% (USA 11.3%, Europe 5.7%); incidence 9.7/1,000 patient-years; no disproportionate increase relative to background rate in normal-weight patients
Outcome: Overall mortality and cause-specific mortality (bone tumors, cerebral hemorrhage) following rhGH treatment in childhood
Effect Size: Significantly increased overall mortality in the French cohort (bone tumors, cerebrovascular events); no increased risk in the Scandinavian-Belgian sub-cohort (n≈2,500)
Community Evidence
Top reported benefits
- Improved fat loss (particularly visceral fat)
- Accelerated post-training recovery
- Improved skin quality and sleep
- Slight increase in lean mass (slow, over months)
Top reported issues
- Water retention in the first weeks
- Carpal tunnel syndrome (numbness in the hands)
- Very high costs (black market and pharmacy prices)
- Slow onset of action (3–6 months until visible results)
- Disappointing muscle gain without concurrent steroid use
- Frequent counterfeits on the black market
Several users in German forums report counterfeit products from the black market and legal risks associated with possession without a prescription [c2, c3]. In r/PEDs and r/steroids, there is ongoing debate as to whether low doses (2–3 IU/day) for anti-aging are justifiable without significant risk; community consensus regards doses >4 IU/day as considerably more risky [c1]. Many users combine HGH with anabolic steroids, complicating benefit-risk assessment [c2].
Scientific Sources
- Somatropin Information
U.S. Food and Drug Administration (2023). FDAALink - Physiology, Growth Hormone – StatPearls
Brinkman JE, Sharma S, Bhatt H, et al. (2023). StatPearls / NCBI BookshelfBLink - Growth hormone and the insulin-like growth factor system in myogenesis
Florini JR, Ewton DZ, Coolican SA (1996). Endocrine ReviewsBPMID:8854047DOI - Short-term administration of supraphysiological recombinant human growth hormone (GH) does not increase maximum endurance exercise capacity in healthy, active young men and women with normal GH-insulin-like growth factor I axes
Lange KH, Larsson B, Flyvbjerg A, et al. (2002). Journal of Clinical Endocrinology & MetabolismAPMID:12364442DOI - Additive effects of growth hormone and testosterone on lipolysis in adipocytes of hypophysectomized rats
Marin P, Krotkiewski M, Bjorntorp P (1995). MetabolismCPMID:7490528DOI - Myostatin is a skeletal muscle target of growth hormone anabolic action
Sartorio A, Agosti F, De Col A, et al. (2008). Journal of Clinical Endocrinology & MetabolismAPMID:17971426DOI - Human growth hormone prevents the protein catabolic side effects of prednisone in humans
Horber FF, Haymond MW (1990). Journal of Clinical InvestigationAPMID:2195062DOI - Growth hormone (GH)-induced insulin resistance is rapidly reversible: an experimental study in GH-deficient adults
Moller N, Jorgensen JOL, Schmitz O, et al. (2013). Journal of Clinical Endocrinology & MetabolismAPMID:23386648DOI - Evening versus morning injections of growth hormone (GH) in GH-deficient patients: effects on 24-hour patterns of circulating hormones and metabolites
Laursen T, Jorgensen JO, Susgaard S, et al. (1990). Journal of Clinical Endocrinology & MetabolismAPMID:2187273DOI - Risk of cancer in patients treated with recombinant human growth hormone in childhood
Carel JC, Ecosse E, Landier F, et al. (2012). Endocrine-Related Cancer / SAGhE study reviewBLink - Somatropin for Growth Hormone Deficiency – NCBI Bookshelf
Donaldson M, Gregory JW, Smith P, et al. (2023). StatPearls / NCBI BookshelfALink - Norditropin (somatropin) injection – Prescribing Information
Novo Nordisk (2017). FDA accessdataALink - OMNITROPE (somatropin) injection – Prescribing Information
Sandoz Inc. (2024). FDA accessdataALink - Somatropin Side Effects: Common, Severe, Long Term
Drugs.com (2024). Drugs.comBLink - Growth hormone stimulates skeletal muscle protein synthesis and antagonizes insulin's antiproteolytic action in humans
Fryburg DA, Gelfand RA, Barrett EJ (1991). Journal of Clinical InvestigationAPMID:1607069DOI - Testosterone supplementation in healthy older men drives GH and IGF-I secretion without potentiating peptidyl secretagogue efficacy
Veldhuis JD, Mielke KL, Bhatt-Lakhman B, et al. (2005). Journal of Clinical Endocrinology & MetabolismAPMID:15870128DOI - Additive effects of growth hormone and testosterone on lipolysis in adipocytes of hypophysectomized rats
Marin P, Krotkiewski M, Bjorntorp P (1995). MetabolismCPMID:7490528DOI - S2e-Leitlinie: Diagnostik des Wachstumshormonmangels im Kindes- und Jugendalter
AWMF, Deutsche Gesellschaft für Kinderheilkunde und Jugendmedizin (2022). AWMF-Register Nr. 174-002ALink - Long-term Safety of Growth Hormone in Adults With Growth Hormone Deficiency: Overview of 15 809 GH-Treated Patients
Abs R et al. (KIMS Study Group) (2022). Journal of Clinical Endocrinology & MetabolismCDOI - Prevalence and incidence of diabetes mellitus in adult patients on growth hormone replacement for growth hormone deficiency: a surveillance database analysis
Attanasio AF, Jung H, Mo D, Chanson P, Bouillon R, Ho KK, Lamberts SW, Strasburger CJ; HypoCCS International Advisory Board (2011). Journal of Clinical Endocrinology & MetabolismCPMID:21543424DOI - GENOTROPIN (somatropin) for injection — US Prescribing Information
Pfizer Inc. (2024). CLink - Treatment of hypopituitarism in patients receiving antiepileptic drugs
Filipsson Nyström H et al. (2014). The Lancet Diabetes & EndocrinologyCDOI - Anlage AntiDopG (zu § 2 Absatz 3) – Anti-Doping-Gesetz
Deutscher Bundestag (2022). Bundesgesetzblatt / buzer.deALink - Growth Hormone and Aging – Endotext
Vance ML, Mauras N, et al. (2019). Endotext / NCBI BookshelfBLink - Clinical and cost-effectiveness of recombinant human growth hormone (somatropin) in adults – NICE report (ScHARR)
University of Sheffield ScHARR, et al. (2003). NICE Technology Appraisal TA64ALink - Recombinant human growth hormone for the treatment of growth disorders in children: a systematic review and economic evaluation
Bryant J, Cave C, Milne R, et al. (2002). NCBI Bookshelf (DARE)ALink - Growth hormone, athletic performance, and aging
Harvard Health Publishing (2022). Harvard HealthBLink - Systematic Review: The Effects of Growth Hormone on Athletic Performance
Liu H, Bravata DM, Olkin I, et al. (2008). Annals of Internal MedicineAPMID:18490691DOI - Somatotropin – DocCheck Flexikon
DocCheck Medical Services GmbH (2023). DocCheck FlexikonBLink
Community Sources
Storage
Unopened
Refrigerator (2–8°C), do not freeze. Store protected from light.
Opened
Depending on the preparation: multi-dose containers after opening 28 days refrigerated (2–8°C) or up to 3 days at room temperature (max. 25°C) — follow product-specific instructions.
Notes
Injection solutions must not be used if they appear cloudy or discolored. Product-specific storage instructions in the summary of product characteristics (e.g., Norditropin, Omnitrope) are binding [s1, s20].