HGH 191AA
also known as Somatropin, rhGH, recombinant human growth hormone, 191-amino-acid hGH
Recombinant 191-amino-acid human growth hormone identical in sequence to endogenous pituitary hGH. FDA-approved (1985) for growth hormone deficiency, Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, AIDS wasting, idiopathic short stature, and other indications. Binds GH receptors systemically to promote linear growth, protein synthesis, lipolysis, and IGF-1 production. Daily subcutaneous administration replaces or supplements deficient endogenous GH.
At a glance
SQ · Daily · Evening preferred
Primary target — Growth hormone receptor (GHR) — JAK2/STAT5 pathway.
Pathway — GHR activation → JAK2/STAT5 → liver IGF-1 synthesis + direct metabolic effects.
Downstream effect — Linear growth, lipolysis, protein synthesis, nitrogen retention, carbohydrate metabolism modulation.
Origin — Recombinant DNA technology — 191 AA, identical to pituitary hGH, no methionyl residue.
Feedback intact — No — exogenous GH bypasses hypothalamic-pituitary axis, suppresses endogenous pulsatility.
| Parameter | Value |
|---|---|
| Pediatric GHD | 0.024–0.034 mg/kg/day SQ6–7× per week dosing typical. Brand-specific ranges. |
| Adult GHD | 0.004–0.016 mg/kg/day SQStart low, titrate based on IGF-1 levels. |
| Turner syndrome | 0.045–0.050 mg/kg/day SQ |
| Idiopathic short stature | 0.037 mg/kg/day SQ |
| AIDS wasting | 0.1 mg/kg/day SQ (high-dose)Short-term indication. Monitor glucose. |
| Frequency | Once daily, typically eveningEvening administration mimics physiological GH pulse. |
| Evidence basis | FDA-approved / decades of RCT data |
| Monitoring | IGF-1, glucose, thyroid function, bone age (children) |
| Duration | Years (children until epiphyseal closure); indefinite (adult GHD) |
Reconstitution
A pure mass-to-volume utility. Enter what you have in the vial; the atlas computes the volume per dose. No prescription information.
FDA-approved for AIDS wasting · multiple RCTs in GHD populations · decades of clinical data
| Outcome | Finding |
|---|---|
| Primary fat target | Visceral and subcutaneous adipose tissue |
| Mechanism | Lipolysis via hormone-sensitive lipase activation, FFA oxidation |
| Effect on lean mass | Significant lean mass increase (protein synthesis, nitrogen retention) |
| Insulin sensitivity | Acute insulin resistance (anti-insulin effect); chronic neutral-to-improved via fat loss |
| IGF-1 elevation | Dose-dependent, significant — primary anabolic mediator |
| Glucose metabolism | Hyperglycemia risk, especially high doses (AIDS wasting) |
| Body composition | ↓ fat mass, ↑ lean mass, ↑ bone mineral density (children) |
| Clinical context | FDA-approved for AIDS wasting (cachexia). Off-label use for body recomposition lacks long-term safety data. |
- — Active malignancy or history of cancer (especially childhood cancer survivors with risk factors)
- — Acute critical illness (post-cardiac surgery, trauma, acute respiratory failure)
- — Diabetic retinopathy (active proliferative or severe non-proliferative)
- — Prader-Willi syndrome with severe obesity, sleep apnea, or respiratory impairment
- — Closed epiphyses (for growth indications)
- — Diabetes mellitus (monitor closely, may require insulin adjustment)
- — Intracranial lesions or history of intracranial hypertension
- — Scoliosis (monitor curve progression)
- — Untreated hypothyroidism (treat before GH initiation)
- — Severe obesity (assess OSA risk, cardiovascular status)
- 01Reconstitution (if lyophilized)
Add diluent (sterile water or bacteriostatic water per manufacturer) to vial. Swirl gently — do not shake. Solution should be clear, colorless. Concentration varies by brand (e.g., 5 mg or 10 mg per vial).
- 02Injection site
Subcutaneous — rotate sites: abdomen, thigh, buttocks, upper arm. Avoid same site within 1 cm for 2 weeks to prevent lipodystrophy.
- 03Timing
Once daily, evening preferred (6–8 PM or pre-sleep). Mimics physiological nocturnal GH secretion. Consistency is critical.
- 04Storage
Unreconstituted: refrigerate 2–8 °C, protect from light. Reconstituted: refrigerate, use within 14–28 days (brand-specific). Do not freeze.
- 05Needle
27–31G, 4–8 mm insulin syringe or pen device. Pinch skin, 45–90° angle depending on subcutaneous thickness.
- 06Monitoring
Baseline and periodic: IGF-1 (target age/sex-adjusted midrange), fasting glucose, HbA1c, thyroid function (TSH, free T4), bone age (children), lipid panel. Fundoscopy if headache/visual symptoms.
Ipamorelin (GHRP) stimulates endogenous GH release, which is redundant when exogenous rhGH is administered. However, ipamorelin may still amplify pulsatility of remaining endogenous secretion in partial GHD or during GH dose titration. Not typically combined in standard clinical practice; more common in experimental or off-label protocols. Limited evidence for additive benefit.
Tesamorelin (GHRH analogue) stimulates endogenous GH secretion, which is unnecessary when exogenous rhGH is already provided. Combining both offers no mechanistic advantage and increases cost, side effects, and IGF-1 elevation risk. Not recommended in clinical practice.
Sources
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