IGF1-LR3
IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3) is a synthetic 83-amino-acid peptide with 13 extra aa + arginine substitution at position 3, extending half-life from 20min (native IGF-1) to 20–30 hours. Binds IGF-1R with high affinity, bypassing IGFBP binding for 3–5x potency. Researched for muscle hypertrophy, hyperplasia, tendon repair, and anti-aging—mimics post-exercise IGF surge.
Edge: Systemic/local growth; hyperplasia potential (new fibers).
Mechanism
- IGF-1R Activation: PI3K/Akt → mTOR → protein synthesis ↑.
- LR3 Mod: ↓IGFBP-3 affinity → free IGF ↑.
- Satellite Cells: Proliferation → nuclei donation.
- Glucose Uptake: Non-insulin mediated.
PK: SubQ/IM; peak 6–12h.
Research Evidence
| Application | Studies/Effects |
|---|---|
| Muscle Growth | Hypertrophy +30%, hyperplasia in rats (J Appl Physiol). |
| Tendon Repair | Collagen ↑2x, strength recovery (animal models). |
| Hyperplasia | New fibers 10–20% (birds/mice; human debate). |
| Anti-Aging | Sarcopenia reversal (aged rats). |
Protocols (Research Contexts)
| Goal | Dose (mcg/day) | Site/Frequency | Cycle |
|---|---|---|---|
| Bulking | 40–80 | IM post-WO | 4w on/4w off |
| Local Growth | 20–50/site | Site-specific inj | 4–6w |
| Recovery | 20–40 | SubQ systemic | 4w |
| Anti-Aging | 10–20 | SubQ AM | 6w on/4 off |
- Recon: 1ml bac water (1mg=1000mcg/0.1ml).
- Stack: w/ CJC/Ipa (GH synergy), MGF (local).
- Hypo Risk: Glucose monitor.
Benefits
- Hyperplasia/Hypertrophy: Myonuclei ↑.
- Tissue Repair: Tendon, ligament gold.
- Fat Loss: Nutrient partitioning.
- Systemic: Bone density, organ repair.
Side Effects & Safety
| Common | Serious | Mitigation |
|---|---|---|
| Hypoglycemia, site irritation | Organ growth (heart/spleen) | Low dose, cycle |
| Water retention | Cancer promotion (IGF-1R) | No active tumors |
- Shutdown: Minimal (not GH axis).
- Labs: IGF-1, glucose, lipids q4w.
Comparisons
| Peptide | Half-Life | Potency | Local? |
|---|---|---|---|
| IGF-1 LR3 | 20–30h | High | Yes |
| IGF-1 DES | 20–30min | Ultra-local | Inj only |
| Native IGF-1 | 20min | Baseline | IV |
| MGF | Hours | Mechano | Local |
Status
- Research Chemical: IGF-1 LR3, Banned WADA; hyperplasia controversial.
- UK: Strict research only.
Disclaimer: Research-only; advanced monitoring required.




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