IGF-1 LR3
Also known as: Long R3 IGF-1, Long Arginine IGF-1
Modified Growth Factor Analog | Muscle Growth
Overview
IGF-1 LR3 is a synthetic 83-amino acid analog of insulin-like growth factor-1 that has never been approved for human use. The N-terminal extension and R3 substitution reduce binding protein interaction, maintaining elevated free circulating levels with ~3x greater potency than native IGF-1.
Key benefits
- Approximately 3x more potent than native IGF-1
- Promotes muscle hypertrophy and hyperplasia in animal models
- 15-20% lean mass gains observed in 4-week rat studies
- Anti-catabolic effects preserve muscle during cachexia
- 20-30 hour half-life for sustained effects
Mechanism of action
Functions as a full IGF-1 receptor agonist activating PI3K/Akt/mTOR and MAPK/ERK pathways. The modifications prevent protein sequestration, maintaining elevated free circulating levels for extended anabolic effects.
Molecular data
- Type
- Synthetic IGF-1 analog
- Half-life
- 20-30 hours
Indications
What the research community uses this compound for, with self-reported effectiveness.
Muscle Growth
Tissue Repair
Metabolic
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Delivery method
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| — | 20-30mcg | Once daily post-workout | — |
| — | 40-60mcg | Once daily | — |
| — | 80-100mcg | Once or split AM/PM | — |
| — | 10-20mcg | Once daily | — |
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Hypoglycemia (lasting up to 30 hours) - CRITICAL
- Water retention
- Joint stiffness
- Muscle soreness
- Increased pump during workouts
Contraindications
- NEVER approved for human use - research chemical only
- Cancer history or undiagnosed growths
- May cause organ hypertrophy (heart, intestines)
- WADA prohibited - causes failed drug tests
Monitoring
- CRITICAL: Consume 30-60g fast carbohydrates immediately after injection
- Never inject before sleep (overnight hypoglycemia risk)
- Monitor blood glucose regularly, especially week one
- 4-6 week maximum cycle; equal off-period required
References
Primary literature and clinical-trial data informing this entry.