Fitness & muscle
Somatropin
FDA-approved recombinant growth hormone for deficiency, widely used off-label for performance and body composition.
FDA-approved (GHD treatment) Fitness & muscle Anti-aging Recovery & healing
- Full name
- Recombinant human growth hormone, 191-amino acid
- Also known as
- rHGH, rhGH, synthetic human growth hormone, HGH 191AA
- Regulatory status
- FDA-approved (GHD treatment) | Off-label use widespread
Origin
Recombinant human growth hormone produced via genetic engineering starting in the 1980s, replacing cadaver-derived pituitary extracts. Now available in daily and long-acting pegylated/fusion formulations.
Mechanism
Binds growth hormone receptor (GHR) on target tissues, promoting IGF-1 production in the liver (endocrine) and peripheral tissues (autocrine/paracrine). Stimulates lipolysis, amino acid uptake, protein synthesis in muscle, and bone mineral density.
Research summary
Evidence
Long-acting GH formulations show non-inferiority to daily GH in height velocity and similar safety. Approved for childhood and adult GHD. Off-label performance use is common but carries risks including hyperglycemia, insulin resistance, and carpal tunnel syndrome; long-term safety data in off-label populations is limited.
Evidence tier: FDA-approved (GHD treatment) — see the methodology note for how this is assessed.
Citations
Reported benefits
- increased lean muscle mass
- improved body composition
- enhanced recovery
- increased bone mineral density
Dosing protocols reported in the literature & community
These are protocols reported by compounding pharmacies, published trials, or self-experimentation communities — not a prescription. Start low, especially for anything new.
| Route | Reported protocol |
|---|---|
| Subcutaneous injection | FDA: 0.04-0.1 mg/kg/day (adult GHD). Off-label athletic use: typically 2-6 IU daily or 4-8 IU every other day. |
Side effects
- hyperglycemia
- insulin resistance
- carpal tunnel syndrome
- gynecomastia
- fluid retention
- joint pain
Safety notes
Community & reddit notes (anecdotal — not clinical evidence)
Widely sourced from underground labs and diverted pharmaceutical supply. Common protocols 2-10 IU daily, often stacked with secretagogues. Users report muscle/recovery gains alongside water retention and joint pain.
Related peptides
Mixing compatibility
Pulled from a community-charted mixing-compatibility reference (anecdotal, clinic-use, and community-reported signals) — not a safety guarantee. Verify independently before combining anything.