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

Get it free
ToolsComparePEG-MGF vs Semax

PEG-MGF vs Semax

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

Anabolic & IGF
PEG-MGF
Cognitive Enhancement
Semax
Summary
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.
Semax is a synthetic heptapeptide derived from ACTH developed in Russia. It is a potent nootropic that enhances memory, focus, and provides neuroprotection. Approved in Russia for cognitive disorders, stroke recovery, and traumatic brain injury.
Half-Life
~3 days (due to PEGylation)
Minutes (but effects persist for hours via BDNF induction)
Admin Route
SubQ
Intranasal, SubQ
Research
Typical Dose
200–400 mcg
0.25–1 mg (250–1000 mcg)
Frequency
2–3x per week
1–2 times daily
Key Benefits
  • 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
  • Enhances memory and learning
  • Improves focus and concentration
  • Increases mental energy and motivation
  • Provides neuroprotection via BDNF and NGF upregulation
  • Reduces cognitive decline
  • May alleviate ADHD symptoms
  • Supports recovery from brain injury and stroke
  • Fast-acting — effects within 30–60 minutes
  • Approved in Russia for cognitive disorders and stroke recovery
Side Effects
  • Water retention and localized swelling
  • Potential hypoglycemia at high doses
  • Theoretical cancer growth risk (growth factor)
  • Injection site reactions
  • +1 more
  • Headache (rare, often from higher doses)
  • Anxiety or overstimulation at high doses
  • Sleep disruption if dosed too late
  • Irritability (uncommon)
Stacks With