For in-vitro research use only · Not for human consumption · Not medical advice
A structurally modified analog of IGF-1 engineered to evade binding proteins, giving it dramatically extended activity in research models — up to 20 hours versus minutes.
Your body naturally produces IGF-1 to drive growth and repair, but binding proteins quickly neutralize it. IGF-1 LR3 has been modified to evade those binding proteins, giving it dramatically extended activity in research models — up to 20 hours vs. minutes.
IGF-1 (Insulin-like Growth Factor 1) is one of your body's primary growth signals. It's released mainly by the liver in response to growth hormone, and it tells cells to grow, divide, and resist apoptosis (programmed cell death). The problem is that as soon as IGF-1 enters the bloodstream, a family of six binding proteins (IGFBPs 1-6) grab onto it and regulate — or often limit — its activity. Native IGF-1 has a half-life measured in minutes.
IGF-1 LR3 solves this with two modifications. First, a 13-amino-acid extension at the N-terminus. Second, a substitution of arginine for glutamic acid at position 3 (the "R3" in LR3). Together, these changes reduce IGFBP binding affinity by 100- to 500-fold, resulting in a dramatically longer active half-life — approximately 20 hours in research models.
This extended activity makes IGF-1 LR3 a preferred research tool for studying IGF-1 receptor signaling, PI3K/Akt/mTOR pathway activation, and downstream effects on protein synthesis and cell survival in tissue culture and preclinical models.
The short version: Your body makes IGF-1 for growth and repair, but binding proteins neutralize it within minutes. IGF-1 LR3 has been modified to evade those binding proteins, extending its active life to roughly 20 hours in research settings.
The N-terminal extension and R3 substitution reduce binding protein affinity by 100-500x, allowing the compound to remain active in its free, unbound form for dramatically longer periods.
Activates the canonical IGF-1 receptor cascade — PI3K phosphorylation, Akt activation, and mTOR signaling — the primary intracellular pathway for protein synthesis and cell growth.
Downstream Akt activation promotes protein synthesis (via mTOR/S6K1) and inhibits apoptosis (via BAD phosphorylation), creating a pro-growth, pro-survival cellular environment.
Binding studies demonstrate that the LR3 modification reduces IGFBP affinity by 100-500 fold, resulting in an approximate 20-hour activity window compared to minutes for native IGF-1.
In cell culture models, IGF-1 LR3 has been studied for its ability to activate mTOR/S6K1-mediated protein synthesis at lower concentrations than native IGF-1, due to its extended receptor engagement.
Research has examined IGF-1 LR3 for its ability to promote cell survival through Akt-mediated BAD phosphorylation, reducing programmed cell death in serum-deprived culture conditions.
IGF-1 LR3 has become a standard tool in cell biology research for studying IGF-1R signaling without the confounding variable of rapid binding protein sequestration.
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For in-vitro research use only. Not for human consumption. The information on this page is for educational purposes only and does not constitute medical advice or a recommendation for human use. No claims are made regarding the diagnosis, studyment, is studied in, or prevention of any condition.
