Human Growth Hormone (Somatropin)
Also known as: Recombinant human GH, rhGH, Genotropin, Humatrope, Norditropin
Human Growth Hormone (Somatropin), also called Recombinant human GH or rhGH, is an FDA-approved recombinant growth hormone. Somatropin is recombinant human growth hormone with the natural 191-amino-acid sequence. It binds a preformed growth hormone receptor dimer on target cells, and the conformational change on binding activates receptor-associated JAK2, which phosphorylates STAT5 for transcriptional signalling.
For research use only.
Key Facts
- CAS
- 12629-01-5
- Molecular Weight (MW)
- 22124 g/mol
- Half-life
- 3.0–3.8 hours after subcutaneous injection in the Genotropin and Humatrope labels (7–10 hours in the Norditropin label), because absorption from the injection site is slow; 0.4 hours intravenously (Genotropin label)
- FDA status
- Approved
- Evidence level
- FDA Approved
- Human dose established
- Yes
- Administration Route
- Subcutaneous
- Frequency
- Daily subcutaneous injection; paediatric weekly doses are divided over 6 or 7 days (3, 6 or 7 for Zomacton), and Serostim is given once daily at bedtime
- Last updated
- Oct 5, 2026
- Reviewed
- Aug 30, 2026
- Targets
- Growth hormone receptor
Research summary
FDA-approved recombinant 191-aa human growth hormone for GH deficiency and other labeled indications. WADA prohibits GH at all times (S2).
Peptide Library's Human Growth Hormone (Somatropin) profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Human Growth Hormone (Somatropin) dosage chart
Somatropin, recombinant human growth hormone, has FDA-approved human dosages that depend on the indication and the product. Children are dosed by weight: for growth hormone deficiency 0.16–0.3 mg/kg per week across the current labels, usually divided into subcutaneous injections on 6 or 7 days. Adults with growth hormone deficiency start at about 0.2 mg/day (range 0.15–0.30 mg/day) and are titrated against serum IGF-1, and Serostim for HIV-associated wasting is 0.1 mg/kg once daily at bedtime, up to 6 mg. No label covers anti-ageing, body-composition or performance use in healthy adults.
| Human dosing established | Yes |
|---|---|
| Route | Subcutaneous |
| Frequency | Daily subcutaneous injection; paediatric weekly doses are divided over 6 or 7 days (3, 6 or 7 for Zomacton), and Serostim is given once daily at bedtime |
| Duration studied | Continuous. Paediatric treatment for growth stops when the epiphyses fuse; the adult growth hormone deficiency labels set no fixed course length; the Serostim label has no controlled data beyond 48 weeks |
| Titration | Adult growth hormone deficiency: start at about 0.2 mg/day (range 0.15–0.30 mg/day) and increase every 1–2 months by about 0.1–0.2 mg/day, guided by clinical response, adverse effects and age- and sex-adjusted serum IGF-1; the labels advise a lower start and smaller steps in older patients, and note that oestrogen-replete women and women on oral oestrogen may need higher doses. Children: individualised by growth response. Serostim: weight-banded with no escalation schedule; 0.1 mg/kg every other day should be considered in patients at increased risk of adverse effects. |
| Half-life | 3.0–3.8 hours after subcutaneous injection in the Genotropin and Humatrope labels (7–10 hours in the Norditropin label), because absorption from the injection site is slow; 0.4 hours intravenously (Genotropin label) |
| Evidence level | FDA Approved |
| Last reviewed | 2026-10-05 |
Research-reported dosing
Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| FDA label — Genotropin, adult growth hormone deficiencyFDA-approved label · FDA prescribing information | Adults with adult-onset or childhood-onset growth hormone deficiency | Non-weight based: about 0.2 mg/day to start (range 0.15–0.30 mg/day), increased every 1–2 months by about 0.1–0.2 mg/day. Weight based: not more than 0.04 mg/kg/week to start, increased at 4–8 week intervals to not more than 0.08 mg/kg/week | Subcutaneous, thigh, buttocks or abdomen, rotating sites; not intravenously | Daily; the weekly dose is divided into 6 or 7 injections | Continuous; titrated against clinical response, adverse effects and age- and sex-adjusted serum IGF-I | Replacement of endogenous growth hormone | GENOTROPIN (somatropin) for injection — FDA prescribing information, DailyMed |
| FDA label — Humatrope, paediatric growth hormone deficiencyFDA-approved label · FDA prescribing information | Children with growth failure due to inadequate secretion of endogenous growth hormone | 0.18–0.3 mg/kg/week (0.026–0.043 mg/kg/day) | Subcutaneous, back of the upper arm, abdomen, buttock or thigh, rotating sites | Weekly dose divided into equal doses given 6 or 7 days per week | Individualised by growth response; stopped for linear growth once the epiphyses fuse | Linear growth | HUMATROPE (somatropin) for injection — FDA prescribing information, DailyMed |
| FDA label — Serostim, HIV-associated wasting or cachexiaFDA-approved label · FDA prescribing information | Adults with HIV and wasting or cachexia, on concomitant antiretroviral therapy | 0.1 mg/kg, up to 6 mg: 6 mg above 55 kg, 5 mg at 45–55 kg, 4 mg at 35–45 kg, 0.1 mg/kg below 35 kg | Subcutaneous, thigh, upper arm, abdomen or buttock, rotating sites | Once daily at bedtime; 0.1 mg/kg every other day should be considered in patients at increased risk of adverse effects such as glucose intolerance | Most of the effect was apparent after 12 weeks; no controlled data beyond 48 weeks | Lean body mass, body weight and physical endurance | SEROSTIM (somatropin) for injection — FDA prescribing information, DailyMed |
| Healthy adults aged 65–88 — randomised trial (Blackman et al., 2002)Clinical trial · Randomised double-blind placebo-controlled factorial trial of growth hormone and sex steroids | Healthy community-dwelling women (n=57) and men (n=74) aged 65 to 88 | 30 mcg/kg to start, reduced to 20 mcg/kg | Subcutaneous | 3 times weekly | 26 weeks | Lean body mass rose and fat mass fell; strength did not increase significantly except a marginal gain with growth hormone plus testosterone in men; diabetes or glucose intolerance occurred in 18 men given growth hormone versus 7 not given it | Blackman MR et al. Growth hormone and sex steroid administration in healthy aged women and men: a randomized controlled trial. JAMA. 2002. |
| Recreational athletes — randomised trial (Meinhardt et al., 2010)Clinical trial · Randomised placebo-controlled blinded trial, with testosterone arms in men | Recreationally trained adults, 63 men and 33 women, mean age 27.9 | 2 mg/day | Subcutaneous | Daily | 8 weeks, then a 6-week washout | Fat mass fell and lean body mass rose through extracellular water; sprint capacity rose by 3.9% and the gain was lost 6 weeks after stopping; endurance, strength and power did not change significantly | Meinhardt U et al. The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial. Ann Intern Med. 2010. |
Where sources disagree
- There is no single somatropin dose. Children are dosed by body weight per week, and the figure depends on both indication and product: for growth hormone deficiency the labels give 0.16–0.24 mg/kg/week (Genotropin, Omnitrope), 0.17–0.24 mg/kg/week (Norditropin) and 0.18–0.3 mg/kg/week (Humatrope, Zomacton), while children born small for gestational age may receive up to 0.47–0.48 mg/kg/week. Adults with growth hormone deficiency are instead started at about 0.2 mg/day and titrated against serum IGF-1; a paediatric per-kilogram figure applied to an adult gives several times the adult starting dose.
- Even for adult growth hormone deficiency the labels are not interchangeable. All five daily somatropin labels reviewed allow a start of about 0.2 mg/day (range 0.15–0.30 mg/day), rising by about 0.1–0.2 mg/day every 1–2 months, but their weight-based alternatives differ: not more than 0.04 rising to not more than 0.08 mg/kg/week (Genotropin, Omnitrope), 0.006 rising to a maximum of 0.0125 mg/kg daily (Humatrope, Zomacton), and 0.004 rising to a maximum of 0.016 mg/kg daily (Norditropin). The Humatrope, Zomacton and Norditropin labels do not recommend the weight-based option for obese patients.
- The Serostim regimen for HIV-associated wasting, up to 6 mg once daily, is 30 times the usual adult growth hormone deficiency starting dose of about 0.2 mg/day. The label ties it to adults with HIV wasting or cachexia on antiretroviral therapy and has no controlled data beyond 48 weeks; it is not a reference point for any other use.
- Sogroya (somapacitan), Skytrofa (lonapegsomatropin) and Ngenla (somatrogon) are once-weekly growth hormone products with labels of their own. Somapacitan is a growth hormone analogue carrying an albumin-binding side chain, somatrogon is growth hormone fused to peptides from the beta chain of hCG, and lonapegsomatropin is a prodrug that releases somatropin from a polyethylene glycol carrier. Their doses do not convert to daily somatropin: Ngenla's paediatric dose of 0.66 mg/kg once weekly is more than double the weekly total in any daily somatropin label for the same indication.
- No somatropin label covers anti-ageing, body composition or athletic performance in healthy adults. In the United States, 21 U.S.C. 333(e) makes it a federal offence to knowingly distribute human growth hormone, or possess it with intent to distribute, for any use in humans other than the treatment of a disease or other recognised medical condition authorised by the FDA and ordered by a physician.
- Trials in healthy people show changes in body composition more than in function. A systematic review of randomised trials in healthy older adults (Liu et al., Annals of Internal Medicine, 2007) found about 2.1 kg more lean mass and 2.1 kg less fat with no significant change in weight, more soft-tissue oedema, joint pain, carpal tunnel syndrome and gynaecomastia, and concluded that growth hormone cannot be recommended as an anti-ageing therapy. A companion review of young, fit participants (Liu et al., 2008) found lean mass rose but strength and exercise capacity did not appear to improve.
- Material sold as "HGH" outside the prescription supply chain, including research-labelled vials, is not any of the labelled products: its identity, content and sterility are not covered by the labels cited here, and their regimens do not describe it. DailyMed also lists homeopathic "HGH" preparations, one naming somatropin at 6C, 100C and 200C dilutions; those are not somatropin dosage forms.
- US labels dose somatropin in milligrams. Where a label converts, it uses about 3 IU per mg: the Humatrope label lists its 6, 12 and 24 mg cartridges as 18, 36 and 72 IU. The same label also gives 0.1 mg/kg as 0.27 IU/kg, so the ratio is a convention rather than an exact constant, and a figure quoted in IU has to be converted before it can be compared with a label dose.
Reconstitution
Common research vial sizes: 4 mg (Serostim), 5 mg (Zomacton or Serostim), 6 mg (Serostim), 10 mg (Zomacton).
| Vial | Bacteriostatic water | Concentration | Per 0.01 mL |
|---|---|---|---|
| 5 mg (Zomacton) | 5 mL supplied bacteriostatic saline | 1 mg/mL | 10 mcg per 0.01 mL |
| 5 mg (Zomacton) | 1 mL supplied bacteriostatic saline | 5 mg/mL | 50 mcg per 0.01 mL |
| 10 mg (Zomacton) | 1 mL supplied bacteriostatic water | 10 mg/mL | 100 mcg per 0.01 mL |
| 6 mg (Serostim, single dose) | 1 mL supplied sterile water | 6 mg/mL | 60 mcg per 0.01 mL |
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Reconstitution Guide
- Reconstitute only with supplied diluent or bacteriostatic water per product instructions (varies by brand/device)
- Injection Sites
- AbdomenThighUpper arm (fatty area)
- Concentration Example
- 10 mg vial ≈ 30 IU total (using 1 mg ≈ 3 IU)
- Timing Notes
- Often administered in the evening for physiologic mimicry (clinical practice varies)
- Expected Onset
- Weeks to months depending on endpoint (IGF-1, body composition, growth)
Sequence & molecular data
| Amino acid sequence | 191 amino acids (recombinant human growth hormone) |
|---|---|
| Molecular formula | C990H1529N263O299S7 |
| Molecular weight | 22124 g/mol |
| CAS number | 12629-01-5 |
| Half-life | ~3 hours (SC/IM absorption-limited; serum decline ~3–5 hours) |
| Appearance | White lyophilized powder (reconstituted for injection) |
| Formulation | Lyophilized Powder |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Somatropin is recombinant human growth hormone with the natural 191-amino-acid sequence. It binds a preformed growth hormone receptor dimer on target cells, and the conformational change on binding activates receptor-associated JAK2, which phosphorylates STAT5 for transcriptional signalling. Effects fall into two groups. Indirect anabolic effects are mediated by hepatic IGF-1, induced by GH and responsible for linear growth at the epiphyseal plates. Direct effects are largely metabolic and include stimulation of lipolysis in adipose tissue and induction of hepatic and peripheral insulin resistance, which is why glucose tolerance can worsen during treatment.
Origin
Recombinant human somatropin.
Targets
Studies
- Efficacy and Safety of Weekly Somatrogon vs Daily Somatropin in Children With Growth Hormone Deficiency: A Phase 3 Study
- Weekly Lonapegsomatropin in Treatment-Naïve Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial
- Safety and Effectiveness of Recombinant Human Growth Hormone in Children with Turner Syndrome: Data from the PATRO Children Study
- [Multiple clinical effects of recombinant human growth hormone therapy]
- Recombinant human growth hormone treatment of Floating-Harbor syndrome: a case report and literature review
Regulatory & research status
Human Growth Hormone (Somatropin) is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.
| FDA status | Approved |
|---|---|
| Availability | Prescription-Only |
| WADA (sport) | Banned in Sport |
| Library classification | FDA-Approved |
Benefits
Human Growth Hormone (Somatropin) side effects
The effects below are drawn from Human Growth Hormone (Somatropin)'s prescribing information, which lists the full adverse-reaction data.
Side Effects
- Edema
- Arthralgia
- Carpal tunnel
- Hyperglycemia
- Intracranial hypertension
Contraindications
- Active malignancy
- Acute critical illness
- Diabetic retinopathy (proliferative/severe)
- Hypersensitivity to product components
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Human Growth Hormone (Somatropin): frequently asked questions
What is Human Growth Hormone (Somatropin)?
FDA-approved recombinant 191-aa human growth hormone for GH deficiency and other labeled indications. WADA prohibits GH at all times (S2).
How does Human Growth Hormone (Somatropin) work?
Somatropin is recombinant human growth hormone with the natural 191-amino-acid sequence. It binds a preformed growth hormone receptor dimer on target cells, and the conformational change on binding activates receptor-associated JAK2, which phosphorylates STAT5 for transcriptional signalling.
Is Human Growth Hormone (Somatropin) FDA approved?
Yes. Human Growth Hormone (Somatropin) is approved by the FDA, and approved products are prescription medicines. Approval is always for specific indications studied in clinical trials, so an approved status does not mean the compound is approved for every use it is discussed for. Research-chemical material sold under the same name is not the approved product.
What is the half-life of Human Growth Hormone (Somatropin)?
Reported half-life for Human Growth Hormone (Somatropin) is ~3 hours (SC/IM absorption-limited; serum decline ~3–5 hours). Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied.
What is the amino acid sequence of Human Growth Hormone (Somatropin)?
Human Growth Hormone (Somatropin) has the sequence 191 amino acids (recombinant human growth hormone). Its molecular formula is C990H1529N263O299S7.
Is Human Growth Hormone (Somatropin) banned in sport?
Human Growth Hormone (Somatropin) is recorded here as prohibited in sport. Athletes subject to anti-doping rules should check the current WADA Prohibited List directly, since it is revised annually and classifications change.
References
- FDA somatropin class labeling exampleExternal reference
- WADA Prohibited List 2026External reference
- Efficacy and Safety of Weekly Somatrogon vs Daily Somatropin in Children With Growth Hormone Deficiency: A Phase 3 Study — J Clin Endocrinol Metab, 2022External reference
- Weekly Lonapegsomatropin in Treatment-Naïve Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial — J Clin Endocrinol Metab, 2021External reference
- Safety and Effectiveness of Recombinant Human Growth Hormone in Children with Turner Syndrome: Data from the PATRO Children Study — Horm Res Paediatr, 2021External reference
- [Multiple clinical effects of recombinant human growth hormone therapy] — Zhongguo Dang Dai Er Ke Za Zhi, 2026External reference
- Recombinant human growth hormone treatment of Floating-Harbor syndrome: a case report and literature review — BMC Pediatr, 2025External reference
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Oct 5, 2026 · Version 2
This Human Growth Hormone (Somatropin) profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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