IGF-1 LR3 (Long R3 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.

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.

15-20% lean mass gains in 4 weeks through satellite cell activation (rat studies).

Cancer cachexia rats maintained 30% more muscle versus placebo.

Creates new muscle fibers via satellite cell differentiation.

Accelerated wound healing in animal models.

Mechanism

15-20% lean mass gains in 4 weeks through satellite cell activation (rat studies).

Research areas

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.
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.
15-20% lean mass gains in 4 weeks through satellite cell activation (rat studies).
Cancer cachexia rats maintained 30% more muscle versus placebo.
Creates new muscle fibers via satellite cell differentiation.
Accelerated wound healing in animal models.
Enhanced connective tissue repair.
Directs nutrients toward muscle tissue.
Enhanced lipolysis through IGF-1 pathway.

Research notes

Hypoglycemia (lasting up to 30 hours) - CRITICAL
Water retention
Joint stiffness
Muscle soreness
Increased pump during workouts
Severe or recurring hypoglycemia despite carbohydrate intake
Unusual growths, lumps, or rapid mole changes
Severe joint pain or carpal tunnel symptoms
Persistent nausea, headaches, or vision changes
Signs of organ enlargement
Extreme fatigue or mental fog
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

References

FAQs

Why is IGF-1 LR3 called 'long R3'?

The N-terminal extension and R3 (arginine) substitution reduce binding to IGF binding proteins, allowing the peptide to circulate freely for 20-30 hours instead of being sequestered. This gives it approximately 3x greater potency and systemic presence than native IGF-1.

Can I take IGF-1 LR3 with HGH?

Not recommended. Both are IGF-1 pathway agonists, and combining them creates excessive IGF-1 levels with amplified side effects including severe hypoglycemia, joint pain, organ enlargement risk, and carpal tunnel symptoms.

How long can I safely use IGF-1 LR3?

Maximum recommended cycle is 4-6 weeks with equal off-time. Prolonged use risks receptor desensitization, excessive organ growth, and cumulative hypoglycemia danger. Most users run 4-6 week cycles with 4-6 weeks off between.

What happens if my blood sugar drops dangerously low on IGF-1 LR3?

Severe hypoglycemia from IGF-1 LR3 can last 20-30 hours due to the long half-life. Consume 30-60g fast carbs immediately after injection and keep glucose tablets handy. Never inject before sleep. Consider having glucagon available for emergency hypoglycemia.