📈HGH Somatropin
Recombinant human growth hormone (191 aa). The upstream GH/IGF-1 axis activator. FDA-approved since 1985. Drives body composition, bone density, wound healing and metabolic function via JAK2/STAT5b.
191-amino acid single chainWhat Is HGH Somatropin?
Human Growth Hormone (HGH / somatropin) is a 191-amino-acid single-chain polypeptide secreted by somatotroph cells of the anterior pituitary. Recombinant HGH (rHGH) has been FDA-approved since 1985 for GHD, Turner syndrome, Prader-Willi syndrome, CKD, and AIDS-related wasting.
Molecular Profile
- Synonyms — Somatropin, growth hormone, GH, hGH, rhGH, GH-N, somatotropin
- CAS Registry Number — 12629-01-5 (191-aa somatropin)
- Molecular formula — C990H1528N262O300S7 (mature, oxidised, 2 disulfides)
- Molecular weight — ≈22,124 Da (≈22.1 kDa)
- Disulfide bonds — 2 (Cys53–Cys165, Cys182–Cys189)
- UniProt — P01241 (SOMA_HUMAN)
- Receptor — Growth hormone receptor (GHR), a class I cytokine receptor with no intrinsic kinase activity of its own
- Potency standard — ≈3 IU per mg by the WHO 2nd International Standard for somatropin (NIBSC 98/574) — see the reconstitution calculator for the IU⇄mg arithmetic
Key Mechanisms
- JAK2 / STAT5b — primary signalling cascade driving hepatic IGF-1 production
- MAPK / ERK — cell proliferation, differentiation, anti-apoptotic effects
- PI3K / Akt / mTOR — protein synthesis, glucose uptake, cell survival
- Direct lipolysis — HSL activation in adipocytes shifts substrate use toward FFA
Research Applications
- GH/IGF-1 axis biology and body composition
- Bone density and osteoblast biology
- Wound healing and burn injury recovery
- Aging and anti-aging marker research
- Metabolic syndrome models
HGH vs GH Secretagogues (CJC-1295/Ipamorelin)
Two distinct research strategies exist for studying elevated GH exposure. Direct exogenous supplementation with recombinant HGH bypasses upstream pituitary control entirely, giving researchers a fixed, continuous hormone input independent of endogenous regulation. The alternative — a GHRH analogue like CJC-1295 paired with a ghrelin-receptor agonist like Ipamorelin — pharmacologically stimulates the pituitary's own pulsatile release while preserving the negative-feedback loop that governs the natural GH/IGF-1 axis.
Exogenous HGH is the better fit when a protocol needs sustained, non-pulsatile exposure or a defined hormone-input-vs-tissue-response curve — for example in bone density or wound-healing models. The secretagogue pair is the better fit when the research question depends on preserving the pulsatile pattern itself, such as hepatic STAT5b research or studies of upstream GH-axis regulation.
Key References
- Rudman D et al. "Effects of HGH in men over 60 years old." N Engl J Med, 1990;323:1–6.
- Jorgensen JO et al. "Beneficial effects of GH treatment in GH-deficient adults." Lancet, 1989;1:1221–1225.
Frequently Asked Questions
By the WHO 2nd International Standard for somatropin (NIBSC 98/574), the modern 22 kDa recombinant form is assigned a potency of approximately 3 IU per mg — so a 10 IU vial contains roughly 3.3 mg of peptide. Use the reconstitution calculator to work out a specific vial's concentration.
Recombinant somatropin is the same 191-amino-acid sequence as endogenous pituitary GH, produced instead via recombinant DNA technology rather than extraction from pituitary tissue — the approach that replaced cadaver-derived GH in the 1980s.
Because they represent the two fundamental ways to raise GH exposure in a research model — direct exogenous supply versus pituitary secretagogue stimulation — and the choice changes whether the pulsatile pattern and negative-feedback loop of the natural axis are preserved.