New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

Get it free
ToolsCompareSomatropin (HGH) vs PEG-MGF

Somatropin (HGH) vs PEG-MGF

Side-by-side comparison of key properties, dosing, and research.

Growth Hormone PeptidesAnti-Aging & Longevity
Somatropin (HGH)
Anabolic & IGF
PEG-MGF
Summary
Somatropin is recombinant human growth hormone (rhGH), identical in structure to the 191-amino acid pituitary-derived growth hormone. It is FDA-approved for growth hormone deficiency, short stature, and wasting conditions. Off-label, it is widely explored for body composition, anti-aging, and performance enhancement, though significant risks accompany unsupervised use.
PEG-MGF (Pegylated Mechano Growth Factor) is a modified form of MGF (Mechano Growth Factor) where polyethylene glycol (PEG) chains have been attached to extend its half-life from minutes to days. Native MGF is released locally in muscle in response to mechanical stress and quickly degrades. PEGylation allows systemic administration with sustained circulation, enabling whole-body muscle repair and anabolic signaling rather than the purely local effect of native MGF.
Half-Life
2-3 hours (subcutaneous); 20-30 minutes (intravenous)
~3 days (due to PEGylation)
Admin Route
Subcutaneous, Intramuscular (less common)
SubQ
Research
Typical Dose
0.15-0.3 mg/day (adults); titrated to IGF-1 levels
200–400 mcg
Frequency
Once daily
2–3x per week
Key Benefits
  • Increases lean muscle mass and reduces body fat (particularly visceral)
  • Restores growth hormone deficiency (FDA-approved)
  • Improves bone mineral density
  • Enhances exercise capacity and recovery
  • Supports skin thickness and collagen synthesis
  • Improves lipid profile in GHD patients
  • Explored for anti-aging and cellular regeneration
  • Extended half-life (~3 days) vs native MGF (minutes)
  • Systemic muscle satellite cell activation via subcutaneous injection
  • Promotes muscle fiber repair and hypertrophy throughout the body
  • Enhanced recovery from intense training or muscle injury
  • Synergistic with IGF-1 LR3 and growth hormone peptides
  • Useful in sarcopenia, post-injury recovery, and athletic performance
  • Single injection provides multi-day anabolic signaling
Side Effects
  • Fluid retention and edema (common, dose-dependent)
  • Carpal tunnel syndrome
  • Joint and muscle pain
  • Insulin resistance and elevated blood glucose
  • +3 more
  • Water retention and localized swelling
  • Potential hypoglycemia at high doses
  • Theoretical cancer growth risk (growth factor)
  • Injection site reactions
  • +1 more
Stacks With