Peptide LibrarySomatrogon
Somatrogon is an FDA-approved long-acting growth hormone fusion protein. Somatrogon fuses human growth hormone to three copies of the C-terminal peptide of the human chorionic gonadotropin beta subunit. The added carbohydrate-rich peptide increases hydrodynamic size and sialic acid content, slowing renal filtration and clearance sufficiently for weekly administration while preserving agonism at the growth hormone receptor.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- —
- Half-life
- Effective half-life of about 37.7 hours in children with growth hormone deficiency (population estimate); present in the circulation for about 8 days after the last dose (Ngenla label)
- FDA status
- Approved
- Evidence level
- FDA Approved
- Human dose established
- Yes
- Administration Route
- Subcutaneous
- Frequency
- Once weekly, on the same day each week
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
Research summary
Long-acting recombinant human growth hormone in which the hormone is fused to three copies of the C-terminal peptide of the chorionic gonadotropin beta subunit. The added glycosylation slows clearance enough for once-weekly rather than daily injection. Marketed as Ngenla and FDA-approved for growth hormone deficiency in children, it is a prescription medicine.
Research evidence
- Regulatory review (FDA label)1 reviewed source
- Controlled human trialsNone in reviewed sources
- Early or uncontrolled human studiesNone in reviewed sources
- Lab & animal studiesNone in reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
Peptide Library's Somatrogon 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.
Somatrogon dosage evidence
Somatrogon has an FDA-approved human dosage as Ngenla, for children aged 3 years and older with growth failure due to inadequate secretion of growth hormone. The label dose is 0.66 mg/kg of actual body weight once a week by subcutaneous injection, individualised by growth response. The US label covers no adult use.
| Human dosing established | Yes |
|---|---|
| Studied dose range | 0.66 mg/kg once weekly (weight-based, children) |
| Route | Subcutaneous |
| Frequency | Once weekly, on the same day each week |
| Duration studied | Continuous while treating growth failure |
| Titration | No escalation schedule: the label dose is 0.66 mg/kg once weekly, individualised by growth response. The dosing day can move if at least 3 days separate two doses. |
| Half-life | Effective half-life of about 37.7 hours in children with growth hormone deficiency (population estimate); present in the circulation for about 8 days after the last dose (Ngenla label) |
| Evidence level | FDA Approved |
| Last reviewed | 2026-11-07 |
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 — Ngenla, paediatric growth hormone deficiencyFDA-approved label · FDA prescribing information | Children aged 3 years and older with growth failure due to inadequate secretion of endogenous growth hormone | 0.66 mg/kg of actual body weight | Subcutaneous, abdomen, thighs, buttocks or upper arms, rotating the site weekly | Once weekly | Individualised by growth response | In the label's 52-week phase 3 study (224 treatment-naive prepubertal children), annualised height velocity was 10.1 cm/year with Ngenla and 9.8 cm/year with daily somatropin 0.034 mg/kg/day | NGENLA (somatrogon-ghla) injection — FDA prescribing information, DailyMed |
Where sources disagree
- Ngenla is dosed once a week by body weight. Its 0.66 mg/kg weekly dose does not convert to daily somatropin: in the label's study the daily somatropin comparison arm received 0.034 mg/kg/day.
- The US label is for children aged 3 years and older with growth hormone deficiency. It is not indicated for children with growth failure due to genetically confirmed Prader-Willi syndrome, and it covers no adult, anti-ageing or performance use.
- Somatrogon is growth hormone joined to peptides from the beta chain of hCG, and it comes only in prefilled pens (24 mg and 60 mg) that deliver doses in 0.2 mg or 0.5 mg steps. It is not the same product as daily somatropin or the other once-weekly growth hormones (somapacitan, lonapegsomatropin), whose labels set their own doses.
Science
Mechanism of Action
Somatrogon fuses human growth hormone to three copies of the C-terminal peptide of the human chorionic gonadotropin beta subunit. The added carbohydrate-rich peptide increases hydrodynamic size and sialic acid content, slowing renal filtration and clearance sufficiently for weekly administration while preserving agonism at the growth hormone receptor.
Studies
- Efficacy and Safety of Somapacitan Relative to Somatrogon and Lonapegsomatropin in Pediatric Growth Hormone Deficiency: Systematic Literature Review and Network Meta-analysis
- Efficacy and safety of once-weekly somatrogon in adults with growth hormone deficiency: a randomized phase 3 study
- Efficacy and safety of once-weekly somatrogon following up to 4 years of treatment in Japanese children with growth hormone deficiency: results from an open-label extension of a phase 3 study
- Efficacy and Safety of Weekly Somatrogon vs Daily Somatropin in Children With Growth Hormone Deficiency: A Phase 3 Study
- Long-acting growth hormone in the treatment of growth hormone deficiency in children: a systematic literature review and network meta-analysis
Research statistics
74 PubMed publications · 52.7% human clinical research · 14 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
Regulatory & research status
Somatrogon 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 |
|---|---|
| Research status | Approved product (see FDA status) |
| Availability | Prescription-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | FDA-Approved |
How FDA approval, compounding and research-only status differ
Benefits
—
Somatrogon side effects
No side effects listed yet for this entry.
Storage & stability
This compound is not supplied as a powder to be mixed, so the freeze-dried powder and reconstitution handling described for research peptides does not apply. Storage conditions are product-specific: follow the label or packaging of the product itself.
Somatrogon: frequently asked questions
What is Somatrogon?
Long-acting recombinant human growth hormone in which the hormone is fused to three copies of the C-terminal peptide of the chorionic gonadotropin beta subunit. The added glycosylation slows clearance enough for once-weekly rather than daily injection. Marketed as Ngenla and FDA-approved for growth hormone deficiency in children, it is a prescription medicine.
How does Somatrogon work?
Somatrogon fuses human growth hormone to three copies of the C-terminal peptide of the human chorionic gonadotropin beta subunit. The added carbohydrate-rich peptide increases hydrodynamic size and sialic acid content, slowing renal filtration and clearance sufficiently for weekly administration while preserving agonism at the growth hormone receptor.
Is Somatrogon FDA approved?
Yes. Somatrogon 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 peptides are similar to Somatrogon?
Compounds most often compared with Somatrogon include Human Growth Hormone (Somatropin), Somapacitan, Lonapegsomatropin and Pegvisomant. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Efficacy and Safety of Somapacitan Relative to Somatrogon and Lonapegsomatropin in Pediatric Growth Hormone Deficiency: Systematic Literature Review and Network Meta-analysis — Adv Ther, 2024External reference
- Efficacy and safety of once-weekly somatrogon in adults with growth hormone deficiency: a randomized phase 3 study — Pituitary, 2026External reference
- Efficacy and safety of once-weekly somatrogon following up to 4 years of treatment in Japanese children with growth hormone deficiency: results from an open-label extension of a phase 3 study — Endocr J, 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
- Long-acting growth hormone in the treatment of growth hormone deficiency in children: a systematic literature review and network meta-analysis — Sci Rep, 2024External reference
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
This Somatrogon 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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