HGH (Somatropin)

Human Growth Hormone · Somatropin

Overview

Human Growth Hormone (HGH/Somatropin) is a 191-amino acid polypeptide hormone FDA-approved for pediatric and adult growth hormone deficiency, HIV-associated wasting, and other conditions. It provides both direct and indirect (IGF-1 mediated) anabolic effects.

Binds to GH receptors on target tissues, triggering JAK2-STAT5 signaling pathway. Direct effects include lipolysis, protein synthesis, and metabolic regulation. Indirect effects via IGF-1 promote growth and anabolism. Half-life ~3 hours subcutaneously.

FDA-approved for idiopathic and organic causes, Turner syndrome, Prader-Willi syndrome, SGA, Noonan syndrome, SHOX deficiency.

FDA-approved for childhood-onset or adult-onset causes (pituitary tumors, surgery, radiation, trauma).

FDA-approved to increase lean body mass and body weight in cachexia.

Significant fat loss especially abdominal/visceral fat over 1-3 months.

Mechanism

FDA-approved for idiopathic and organic causes, Turner syndrome, Prader-Willi syndrome, SGA, Noonan syndrome, SHOX deficiency.

Research areas

Human Growth Hormone (HGH/Somatropin) is a 191-amino acid polypeptide hormone FDA-approved for pediatric and adult growth hormone deficiency, HIV-associated wasting, and other conditions. It provides both direct and indirect (IGF-1 mediated) anabolic effects.
Binds to GH receptors on target tissues, triggering JAK2-STAT5 signaling pathway. Direct effects include lipolysis, protein synthesis, and metabolic regulation. Indirect effects via IGF-1 promote growth and anabolism. Half-life ~3 hours subcutaneously.
FDA-approved for idiopathic and organic causes, Turner syndrome, Prader-Willi syndrome, SGA, Noonan syndrome, SHOX deficiency.
FDA-approved for childhood-onset or adult-onset causes (pituitary tumors, surgery, radiation, trauma).
FDA-approved to increase lean body mass and body weight in cachexia.
Significant fat loss especially abdominal/visceral fat over 1-3 months.
Increased muscle mass and improved body composition.
Enhanced exercise recovery and tissue healing.
Improved skin elasticity, texture, and hair/nail growth.
Improved energy, sleep, and quality of life.

Research notes

Water retention and fluid accumulation
Joint pain and stiffness
Carpal tunnel syndrome (usually resolves with dose reduction)
Headaches
Numbness/tingling in hands
Severe or worsening carpal tunnel symptoms
Signs of diabetes (increased thirst, frequent urination, blurred vision)
Severe edema (facial, hand, or feet swelling)
Severe joint/muscle pain unresponsive to dose reduction
New lumps, masses, or rapidly growing moles
Severe headaches or vision changes
Signs of allergic reaction
Gynecomastia (breast tissue growth in males)
Hypothyroid symptoms (fatigue, weight gain, cold intolerance)
Active cancer (may accelerate tumor growth)
Acute critical illness (increased mortality in ICU patients)
Closed epiphyses in children (for growth promotion)
Pregnancy/breastfeeding

Pharmacokinetics

Binds to GH receptors on target tissues, triggering JAK2-STAT5 signaling pathway. Direct effects include lipolysis, protein synthesis, and metabolic regulation. Indirect effects via IGF-1 promote growth and anabolism. Half-life ~3 hours subcutaneously.

References

FAQs

Will HGH unmask thyroid problems?

Yes. HGH unmasks central hypothyroidism in 36-47% of users by increasing T4-to-T3 conversion. Get baseline thyroid labs (TSH, free T4, free T3) before starting and recheck at 6-8 weeks. Many users need T4 supplementation while on HGH.

How much carpal tunnel syndrome should I expect from HGH?

Carpal tunnel symptoms are common (10-30% of users) and typically mild to moderate. They usually resolve with dose reduction. Symptoms typically peak at 2-4 weeks and improve as your body adapts. Starting low and titrating up reduces risk.

Does HGH require continuous use or can I cycle it?

HGH effects are dose-dependent and reversible. Most users cycle 3-6 months on, 1-2 months off to maintain sensitivity and allow recovery of natural GH production. Continuous use is possible but may increase side effect risk over time.

Can HGH cause diabetes?

HGH decreases insulin sensitivity, potentially unmasking pre-diabetes or causing diabetes in susceptible individuals. Monitor fasting glucose and HbA1c regularly. Those with family history of diabetes should proceed cautiously and may need metformin support.