Overview
IGF-1 LR3 (Long R3 IGF-1) is a modified version of insulin-like growth factor 1 with an arginine substitution and a 13-amino-acid N-terminal extension. These modifications extend its half-life from ~20 minutes to roughly 20–30 hours and reduce binding to IGF-binding proteins, leaving more active peptide free in circulation.
Mechanism of action
IGF-1 LR3 binds the IGF-1 receptor on muscle, bone, and other tissues, activating PI3K/Akt/mTOR pathways that drive protein synthesis, satellite-cell proliferation, and hyperplasia (new muscle cell formation).
Reported benefits
- Increased muscle protein synthesis and hyperplasia
- Enhanced nutrient partitioning
- Improved soft-tissue recovery
- Fat metabolism support
- Nerve regeneration in animal models
Research dosing
Research protocols typically use 20–50 mcg daily, often post-workout. Cycles are kept short (3–4 weeks) to limit receptor downregulation.
Considerations
Significantly more potent than native IGF-1. Hypoglycemia risk requires careful timing around meals. Short cycles are preferred to preserve receptor sensitivity.
Research use only. This article is provided for educational purposes and is not medical advice. Products sold on this website are for laboratory research only and are not intended for human consumption. Not evaluated by the FDA.
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