IGF-1 LR3
Also known as: Insulin-like Growth Factor-1 Long R3, Long R3 IGF-1, Increlex (human equivalent)
IGF-1 LR3 is a research compound not approved for human use. It carries clinically significant hypoglycemia risk. This profile is for research and informational purposes only. Not medical advice.
Overview
IGF-1 LR3 (Long Arg3 IGF-1) is a synthetic analogue of Insulin-like Growth Factor 1 with an amino acid substitution at position 3 and a 13-amino acid N-terminal extension. These modifications prevent binding to IGF-binding proteins (IGFBPs), dramatically extending its half-life from ~12 minutes (native IGF-1) to approximately 20–30 hours. IGF-1 LR3 is widely used in research for its ability to promote cellular growth, protein synthesis, hyperplasia, and nutrient uptake into muscle tissue.
Research Summary
In vitro and animal research establishes IGF-1 LR3 as a potent anabolic and growth-promoting agent. It activates the IGF-1 receptor (IGF-1R) and downstream PI3K/Akt and MAPK/Erk pathways, promoting skeletal muscle hypertrophy and satellite cell activation. Its extended half-life makes it far more active systemically than native IGF-1. Research also documents its role in connective tissue repair, nerve regeneration, and fat oxidation. Human research is limited — most data comes from cancer cell biology and athletic performance settings.
Dosing Range
low
20mcg
moderate
50mcg
high
100mcg
Units: mcg · Frequency: Once daily post-workout, on training days only (common protocol)
Dosing ranges are aggregated from preclinical research and community protocols. Not medical dosing guidance.
Administration Routes
Reconstitution Notes
Reconstitute with 1 mL acetic acid (0.1M) or bacteriostatic water. IGF-1 LR3 is sensitive to pH — some researchers prefer acetic acid for initial reconstitution, then diluting further with bacteriostatic saline. Store reconstituted solution at 2–8°C. Use within 30 days.Step-by-step reconstitution guide →
Supplies you'll need
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Reported Side Effects
- Hypoglycemia (clinically significant — monitor blood sugar carefully)
- Jaw and organ growth with chronic high-dose use (theoretical at research doses)
- Fatigue and headaches
- Joint pain
- Swelling or edema at high doses
- Potential pro-proliferative effects in pre-existing cancer cell lines (theoretical)
Research Papers
3 peer-reviewed sourcesCommunity Experiences
Aggregated from public forums. Anecdotal — not clinical evidence.
Community protocols range from 20–100mcg PWO. Users frequently cite rapid muscle fullness and enhanced muscle memory. Hypoglycemia is the most discussed risk, especially at doses above 50mcg.
View original threadAdvanced discussions on site-specific injections, co-administration with GH and insulin, and cycle design. Safety warnings around blood glucose monitoring are consistently emphasized.
View original threadWant to calculate your dose? Use the dosing calculator →