IGF-1 LR3 (Long-Arg3)
Overview
IGF-1 LR3 is a synthetic analogue of insulin-like growth factor 1 with an N-terminal extension of 13 amino acids and a substitution of arginine for glutamic acid at position 3. These modifications reduce binding to IGF-binding proteins, resulting in an extended half-life and increased bioavailability compared to native IGF-1. The peptide promotes anabolic processes including muscle protein synthesis, glucose uptake, and cellular proliferation. IGF-1 LR3 is not approved for human use and is primarily available as a research reagent, though it is sometimes misused in athletic and bodybuilding contexts.
Key Research Findings
No clinical trials have evaluated IGF-1 LR3 for safety or efficacy in humans, and the compound is not approved by the FDA or other major regulatory agencies. Preclinical studies demonstrate potent anabolic and mitogenic effects in cell culture and animal models. The absence of human pharmacokinetic, safety, and controlled efficacy data, combined with concerns about mitogenic risks and off-label misuse, restricts IGF-1 LR3 to experimental research applications.
Subcutaneous injection
Research Phase
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