IGF-1 LR3
IGF-1 LR3 is a synthetic, modified version of Insulin-like Growth Factor-1 with an extended half-life and increased potency. Research highlights its ability to promote muscle cell hyperplasia (growth of new muscle cells), enhance protein synthesis, and improve recovery by resisting deactivation by IGF-binding proteins.
01Dosing reference
02Mechanism of action
Receptor Binding
Binds to the IGF-1 receptor on cell surfaces with high affinity, while resisting binding to IGF-binding proteins (IGFBPs) that normally neutralize standard IGF-1.
Cellular Activation
Triggers intracellular signaling pathways (such as PI3K/AKT) that stimulate amino acid uptake, protein synthesis, and cell proliferation.
Tissue Growth and Repair
Promotes muscle cell hyperplasia and hypertrophy, leading to increased muscle mass and accelerated tissue repair in research models.
03Human evidence
Limited human trials have explored modified IGF-1 variants for severe insulin resistance and muscle wasting conditions, showing improvements in protein metabolism.
Most human data is based on standard IGF-1 (Mecasermin) rather than the LR3 variant specifically, though LR3 is studied for its extended pharmacokinetic profile.
Studies on IGF-1 therapies indicate potential for increasing lean body mass and improving nitrogen balance in catabolic states.
Clinical applications are often limited by the risk of hypoglycemia and other systemic side effects.
04Preclinical evidence
Demonstrated significantly greater potency than standard IGF-1 in stimulating muscle hypertrophy and cellular proliferation in vitro.
Cell culture models using myoblasts and animal models of muscle injury.
Shown to enhance recovery from muscle damage and promote the growth of new muscle fibers (hyperplasia) in animal models.
Rodent models evaluating muscle regeneration post-injury.
05What is known vs. unknown
- Significantly longer half-life (20-30 hours) compared to standard IGF-1 due to decreased affinity for IGF-binding proteins.
- Promotes both muscle hypertrophy (increased cell size) and hyperplasia (increased number of cells).
- Enhances nutrient shuttling and protein synthesis in muscle tissues.
- Often researched for its potential to accelerate recovery from musculoskeletal injuries.
- Long-term safety and potential risks regarding cellular proliferation and cancer progression remain poorly understood.
- Optimal dosing protocols to avoid insulin receptor cross-activation and subsequent hypoglycemia are not fully established in humans.
- Lack of large-scale, long-term human clinical trials specifically evaluating the LR3 variant.
06Safety & regulatory context
07Compared with IGF-1 DES
08Appears in protocols
09Glossary
10Knowledge check
11Sources
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