Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| IGF-1 LR3 | MGF (Mechano Growth Factor) | |
|---|---|---|
| Category | Growth Factors | Growth Factors |
| Standard Dose | Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection. | Research indicates 100-200 mcg per injection site, administered bilaterally into target muscles immediately post-workout. |
| Timing | Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days. | Immediately post-workout (within 5-10 minutes) for optimal satellite cell activation. Must be injected directly into the trained muscle. |
| Cycle Duration | 4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization. | 4-6 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.
MGF is the E domain peptide of the IGF-1Ec splice variant, produced when the IGF-1 gene is mechanically spliced in response to muscle damage or exercise. It activates satellite cells (muscle stem cells), promoting their proliferation and preventing premature differentiation. After exercise/injury, IGF-1 gene is first spliced toward MGF (proliferation phase) then shifts to IGF-1Ea (differentiation phase). MGF uniquely drives the initial proliferative response, expanding the pool of myogenic precursor cells before they fuse with existing muscle fibers.
Research indicates 100-200 mcg per injection site, administered bilaterally into target muscles immediately post-workout.
Immediately post-workout (within 5-10 minutes) for optimal satellite cell activation. Must be injected directly into the trained muscle.
4-6 week cycles.
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