Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| IGF-1 LR3 | Thymosin Alpha-1 | |
|---|---|---|
| Category | Growth Factors | Growth Factors |
| Standard Dose | Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection. | Research indicates 1.6 mg administered twice weekly via subcutaneous injection. |
| Timing | Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days. | Morning administration preferred. No food timing restrictions. |
| Cycle Duration | 4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization. | 8-12 week cycles, with periodic breaks. Some protocols use continuous low-dose maintenance. |
| Evidence Level | moderate_human | strong_human |
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.
Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus that acts as a pleiotropic immune modulator through Toll-like receptors (TLR2, TLR3, TLR4, TLR7, TLR9) on myeloid and plasmacytoid dendritic cells. It activates downstream IRF3, NF-kB, p38MAPK, and MyD88 signaling pathways to promote cytokine production. It modulates TNF-alpha, IFN-gamma, and IL-2 in CD4+ and CD8+ T lymphocytes by upregulating CD40/CD40L and downregulating PD-L1/PD-1 expression, enhancing both innate and adaptive immunity.
Research indicates 1.6 mg administered twice weekly via subcutaneous injection.
Morning administration preferred. No food timing restrictions.
8-12 week cycles, with periodic breaks. Some protocols use continuous low-dose maintenance.
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