HGH 191AA refers to recombinant human growth hormone (somatropin) — a 191-amino acid, single-chain polypeptide (MW ~22,124 g/mol) identical in sequence to endogenous pituitary growth hormone. It is FDA-approved for growth hormone deficiency in children and adults, Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, and HIV-associated wasting. In the peptide community, "191AA" distinguishes legitimate somatropin from the older 192-amino acid variant (somatrem, which had an extra methionine and higher immunogenicity).
4 independent Janoshik purity tests cover HGH 191AA across 2 vendors. Results range from 95.9% to 96.7%.
Category: Growth Hormone. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved (multiple indications). Numerous brand-name products available worldwide.
HGH 191AA binds to the growth hormone receptor (GHR) on target cells, triggering JAK2-STAT5 signaling, which drives transcription of IGF-1 and other growth factors. Direct effects include lipolysis (fat breakdown), increased protein synthesis, and glucose mobilization. Indirect effects via hepatic…
Safety considerations: Common: injection site reactions, fluid retention, joint pain/stiffness, carpal tunnel syndrome; Metabolic: insulin resistance, hyperglycemia (dose-dependent), may precipitate diabetes; Endocrine: gynecomastia, hypothyroidism (may unmask central hypothyroidism).
Reviewed by the PeptideAtlas Editorial Team.
| Molecular weight | ~22,124 g/mol |
|---|---|
| Half-life | ~3-5 hours (SC) |
| Bioavailability | ~63-80% SC |
| Production method | recombinant |
| Anti-doping status | Prohibited in sport (WADA) |
| US regulatory status | FDA-approved. Multiple brands: Genotropin, Humatrope, Norditropin, Saizen, Omnitrope, Zomacton. Schedule III controlled substance (Anabolic Steroids Control Act). |
| Vendor | Best tested purity |
|---|---|
| Penguin Peptides | 96.7% |
| Panda Peptides LLC | 95.9% |
Related peptides: Somatropin (rHGH), CJC-1295 with DAC.
It refers to the 191-amino acid sequence of natural human growth hormone. This distinguishes it from the older 192AA variant (somatrem) which had an extra methionine residue and caused immune reactions. All modern pharmaceutical GH is 191AA.
GH replacement in genuinely deficient adults is safe and beneficial. However, using supraphysiological doses in non-deficient individuals carries risks including insulin resistance, joint problems, fluid retention, and theoretical cancer risk from elevated IGF-1. Long-term safety in healthy adults is not established.
Brand-name GH costs $800-$3000+ per month depending on dose and brand. This is a primary driver of the grey-market GH industry, which offers unverified products at much lower prices.
Coverage on this site: Alcohol Wipes: Key to Sterile Peptide Preparation.