Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| IGF-1 LR3 | PEG-MGF | |
|---|---|---|
| Category | Growth Factors | Growth Factors |
| Standard Dose | Research indicates 20-50 mcg daily 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. | — |
| Cycle Duration | 4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization. | — |
| Evidence Level | moderate_human | Preclinical |
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.
Pegylated mechano growth factor analog discussed in muscle repair and hypertrophy contexts with limited human evidence.
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