Peptide LibrarySomapacitan
Somapacitan is an FDA-approved long-acting growth hormone. Somapacitan is a human growth hormone analog carrying a single substitution with an attached albumin-binding side chain. Reversible, non-covalent binding to endogenous albumin slows renal clearance and receptor-mediated elimination, extending the half-life enough to support weekly dosing while the molecule still signals through the normal growth hormone receptor and JAK2/STAT5 pathway.
For research use only.
Key Facts
- CAS
- 1338578-34-9
- Molecular Weight (MW)
- 1310.5 g/mol
- Half-life
- About 2 to 3 days in adults with growth hormone deficiency; about 34 hours in children with growth hormone deficiency at 0.16 mg/kg/week (Sogroya label)
- FDA status
- Approved
- Evidence level
- FDA Approved
- Human dose established
- Yes
- Administration Route
- Subcutaneous
- Frequency
- Once weekly
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
Research summary
Once-weekly albumin-binding growth hormone derivative approved for growth hormone deficiency in adults and in children. It reduces injection frequency from daily to weekly.
Research evidence
- Regulatory review (FDA label)3 reviewed sources
- 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 Somapacitan 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.
Somapacitan dosage evidence
Somapacitan has FDA-approved human dosages as Sogroya, given by subcutaneous injection once a week. Children aged 2.5 years and older are dosed by weight: 0.16 mg/kg once weekly for growth hormone deficiency and 0.24 mg/kg once weekly for short stature after being born small for gestational age, Noonan syndrome or idiopathic short stature. Adults with growth hormone deficiency start at 1.5 mg once weekly and are titrated against serum IGF-1 to at most 8 mg once weekly.
| Human dosing established | Yes |
|---|---|
| Route | Subcutaneous |
| Frequency | Once weekly |
| Duration studied | Continuous |
| Titration | Adults: start at 1.5 mg once weekly (1 mg from age 65 and in moderate hepatic impairment, 2 mg for women on oral oestrogen), then raise by about 0.5–1.5 mg every 2–4 weeks guided by clinical response and serum IGF-1 drawn 3–4 days after a dose; maximum 8 mg once weekly (4 mg in moderate hepatic impairment). Children: individualised by growth response. |
| Half-life | About 2 to 3 days in adults with growth hormone deficiency; about 34 hours in children with growth hormone deficiency at 0.16 mg/kg/week (Sogroya 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 — Sogroya, paediatric growth hormone deficiencyFDA-approved label · FDA prescribing information | Children aged 2.5 years and older with growth failure due to inadequate secretion of endogenous growth hormone | 0.16 mg/kg of actual body weight | Subcutaneous, upper arms, thigh, abdomen or buttocks, rotating the site weekly | Once weekly | Individualised by growth response | In the label's 52-week phase 3 study (200 treatment-naive children), annualised height velocity was 11.2 cm/year with Sogroya and 11.7 cm/year with daily somatropin 0.034 mg/kg/day | SOGROYA (somapacitan-beco) injection — FDA prescribing information, DailyMed |
| FDA label — Sogroya, small for gestational age, Noonan syndrome, idiopathic short statureFDA-approved label · FDA prescribing information | Children aged 2.5 years and older born small for gestational age without catch-up growth by age 2, or with Noonan syndrome or idiopathic short stature | 0.24 mg/kg of actual body weight | Subcutaneous | Once weekly | Individualised by growth response | Linear growth | SOGROYA (somapacitan-beco) injection — FDA prescribing information, DailyMed |
| FDA label — Sogroya, adult growth hormone deficiencyFDA-approved label · FDA prescribing information | Adults with growth hormone deficiency | 1.5 mg to start (1 mg from age 65; 2 mg with oral oestrogen), titrated to a maximum of 8 mg | Subcutaneous | Once weekly | Continuous; titrated against clinical response and serum IGF-1 | Replacement of endogenous growth hormone | SOGROYA (somapacitan-beco) injection — FDA prescribing information, DailyMed |
Where sources disagree
- Children are dosed in mg/kg and adults in fixed milligrams. A paediatric per-kilogram figure applied to an adult gives a dose far above the adult starting dose of 1.5 mg once weekly.
- Somapacitan is a growth hormone analogue with a side chain that binds albumin, which is what slows its clearance. Its once-weekly doses do not convert to daily somatropin or to the other once-weekly products (somatrogon, lonapegsomatropin), which have labels of their own.
- The label does not recommend Sogroya in severe hepatic impairment, or for children with moderate hepatic impairment. It comes only in prefilled pens (5, 10 and 15 mg) and covers no anti-ageing or performance use.
Sequence & molecular data
| Molecular formula | C54H95N13O20S2 |
|---|---|
| Molecular weight | 1310.5 g/mol |
| CAS number | 1338578-34-9 |
| PubChem CID | 129894493 |
| FDA UNII | 8FOJ430U94 |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Somapacitan is a human growth hormone analog carrying a single substitution with an attached albumin-binding side chain. Reversible, non-covalent binding to endogenous albumin slows renal clearance and receptor-mediated elimination, extending the half-life enough to support weekly dosing while the molecule still signals through the normal growth hormone receptor and JAK2/STAT5 pathway.
Studies
- Efficacy and Safety of Somapacitan Relative to Somatrogon and Lonapegsomatropin in Pediatric Growth Hormone Deficiency: Systematic Literature Review and Network Meta-analysis
- Once-weekly somapacitan in children with Noonan syndrome: randomized controlled phase 3 trial
- Somapacitan in children born small for gestational age: a randomized controlled phase 3 trial
- Somapacitan in children born small for gestational age: 4-year results from phase 2
- Efficacy, safety, and insulin-like growth factor I of weekly somapacitan in children with growth hormone deficiency: 3-year results from REAL4
Research statistics
90 PubMed publications · 54.4% human clinical research · 21 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
Somapacitan 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
—
Somapacitan 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.
Somapacitan: frequently asked questions
What is Somapacitan?
Once-weekly albumin-binding growth hormone derivative approved for growth hormone deficiency in adults and in children. It reduces injection frequency from daily to weekly.
How does Somapacitan work?
Somapacitan is a human growth hormone analog carrying a single substitution with an attached albumin-binding side chain. Reversible, non-covalent binding to endogenous albumin slows renal clearance and receptor-mediated elimination, extending the half-life enough to support weekly dosing while the molecule still signals through the normal growth hormone receptor and JAK2/STAT5 pathway.
Is Somapacitan FDA approved?
Yes. Somapacitan 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 Somapacitan?
Compounds most often compared with Somapacitan include Human Growth Hormone (Somatropin), Lonapegsomatropin, Somatrogon 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
- Once-weekly somapacitan in children with Noonan syndrome: randomized controlled phase 3 trial — Eur J Endocrinol, 2026External reference
- Somapacitan in children born small for gestational age: a randomized controlled phase 3 trial — Eur J Endocrinol, 2026External reference
- Somapacitan in children born small for gestational age: 4-year results from phase 2 — Eur J Endocrinol, 2026External reference
- Efficacy, safety, and insulin-like growth factor I of weekly somapacitan in children with growth hormone deficiency: 3-year results from REAL4 — Eur J Endocrinol, 2025External reference
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
This Somapacitan 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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