IGF-1 LR3
Long-acting IGF-1 analogue with reduced IGFBP binding; half-life ~20 hours vs ~10 min for native IGF-1. Studied for satellite cell activation, skeletal muscle hypertrophy, and mTOR pathway research. Limited US availability — verify stock before ordering.
What Research Shows
Studied for PI3K/Akt/mTOR-mediated protein synthesis, satellite cell (Pax7+) proliferation, and skeletal muscle hypertrophy via IGFBP-independent receptor engagement. Studies measure fibre cross-sectional area (immunofluorescence), p70S6K phosphorylation, and lean body mass by DXA. Strong mechanistic evidence; availability limited.
Pros & Cons
- +IGF-1 LR3 half-life of ~20 hours vs ~10 minutes for native IGF-1 — practical for in vivo dosing without continuous infusion
- +Directly engages mTOR pathway — one of the most studied anabolic signalling cascades
- +Strong published evidence for satellite cell activation and lean mass increase in animal models
- +TB-500 provides synergistic effect by improving vascular supply and satellite cell homing without direct anabolic stimulation
- +Well-characterised mechanism enables precise experimental design
- −IGF-1 LR3 must be reconstituted in dilute acetic acid, not water — incorrect reconstitution causes tissue damage at injection site
- −Supraphysiological IGF-1 levels carry theoretical oncogenic risk due to broad receptor activity
- −Hypoglycaemia risk at higher doses — blood glucose monitoring recommended in diabetic-prone models
- −IGF-1 LR3 is essentially unavailable from Japan-accessible vendors as of 2026 — contact vendors directly
- −No human clinical data; animal study results may not translate
- −Most expensive category of Japan research peptides
Effects Timeline
Based on published study timelines. Human extrapolation is approximate — individual results vary significantly.
Satellite cell activation (Pax7+/BrdU+ staining) is detectable within 7–14 days in published animal models. Measurable increases in muscle fibre cross-sectional area typically require 4–6 weeks of treatment in rodent studies.
What People Research This For
Practical Questions
Why must IGF-1 LR3 be reconstituted in acetic acid, not bacteriostatic water?
IGF-1 LR3 is poorly soluble at neutral pH. Dilute acetic acid (0.1%) lowers pH to solubilise the peptide. However, the acidic solution must be diluted with sterile PBS to physiological pH before injection — injecting the acetic acid solution undiluted causes significant tissue irritation and necrosis at the injection site.
Is IGF-1 LR3 the same as synthetic IGF-1?
No. IGF-1 LR3 has a modified arginine substitution at position 3 and an extended N-terminal sequence that dramatically reduces its binding to IGF-binding proteins (IGFBPs). This prevents the rapid clearance that limits native IGF-1's half-life to ~10 minutes, extending IGF-1 LR3's half-life to approximately 20 hours. The result is prolonged receptor activation from a single dose.
Where to Buy IGF-1 LR3 in Japan
IGF-1 LR3 has limited Japan vendor availability as of March 2026. Most Japan-accessible vendors do not stock this compound routinely.
Contact vendors directly to check current stock, or see our full Japan vendor comparison for contact details.