Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| IGF-1 LR3 | PEG-MGF (Pegylated Mechano Growth Factor) | |
|---|---|---|
| Category | Growth Factors | Growth Factors |
| Standard Dose | Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection. | Research indicates 200-500 mcg administered 2-3 times per week via subcutaneous or intramuscular injection. |
| Timing | Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days. | On non-training days or several hours post-workout (to avoid competing with natural MGF pulse). Unlike native MGF, timing is more flexible due to extended half-life. |
| Cycle Duration | 4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization. | 4-8 week cycles. |
| Evidence Level | moderate_human | animal_plus_anecdotal |
IGF-1 LR3 (Long Arginine 3-IGF-1) is an 83-amino acid synthetic analog of IGF-1 with an arginine substitution at position 3 and 13 additional N-terminal amino acids. These modifications eliminate binding to IGF-binding proteins, making it approximately 3x more potent than native IGF-1 with a half-life of 20-30 hours (vs 12-15 minutes for native IGF-1). It activates the IGF-1R tyrosine kinase receptor, triggering IRS-1/PI3K/Akt/mTOR and PI3K/Akt/GSK3-beta pathways to drive protein synthesis, muscle hypertrophy, and hyperplasia (new muscle cell formation).
Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection.
Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days.
4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization.
PEG-MGF is the pegylated form of Mechano Growth Factor, where polyethylene glycol (PEG) molecules are covalently attached to protect against rapid enzymatic breakdown. This extends the half-life from 5-7 minutes (native MGF) to approximately 48-72 hours. Like native MGF, it activates satellite cell proliferation, promotes muscle fiber regeneration and hypertrophy, and supports tissue repair. The extended half-life allows for systemic distribution rather than purely local action, enabling subcutaneous rather than intramuscular administration.
Research indicates 200-500 mcg administered 2-3 times per week via subcutaneous or intramuscular injection.
On non-training days or several hours post-workout (to avoid competing with natural MGF pulse). Unlike native MGF, timing is more flexible due to extended half-life.
4-8 week cycles.
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