IGF-1 LR3
Growth factor analog · Also known as Long R3 IGF-1, Long Arg3 IGF-1
What is IGF-1 LR3?
A modified version of insulin-like growth factor 1 with a longer half-life and greater potency than native IGF-1. It promotes muscle growth, recovery, and nutrient uptake.
IGF-1 LR3 is an 83-amino-acid synthetic analog of human IGF-1. It has an arginine substituted at position 3 and 13 additional amino acids at the N-terminus, reducing its affinity for IGF-binding proteins and making it roughly three times more potent than native IGF-1.
Benefits & evidence
How it works
IGF-1 LR3 binds to the IGF-1 receptor on cell surfaces, activating the PI3K/Akt and MAPK signaling cascades. These pathways promote protein synthesis, inhibit protein degradation, and stimulate satellite cell proliferation in muscle tissue.
Because its structural modifications reduce binding to IGF-binding proteins, more of the peptide remains free and active in circulation. This gives it a half-life of 20 to 30 hours compared to about 15 minutes for native IGF-1.
Dosing information
Typical dosing protocol
20-50 mcg/day
Weeks 1-250-100 mcg/day
4-6 week cyclesTypically administered subcutaneously. Cycle length is important due to IGF-1 receptor desensitization.
Side effects
Most side effects tend to improve as your body adjusts.