OnePin Peptide Library · Growth Hormone
IGF-1 LR3
Long R3 IGF-1 · Receptor-Grade IGF-1 · LR3 IGF-1
IGF-1 LR3 (Long R3 Insulin-like Growth Factor 1) is a modified synthetic analog of human IGF-1 with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These modifications dramatically reduce binding to IGF binding proteins (IGFBPs), resulting in a much longer biological half-life (20-30 hours) compared to native IGF-1 (12-15 minutes). This means IGF-1 LR3 remains active in the bloodstream far longer, producing more potent and sustained anabolic effects.,IGF-1 is a key mediator of growth hormone's anabolic effects, playing critical roles in muscle growth, tissue repair, and cellular proliferation. While native IGF-1 (mecasermin/Increlex) is FDA-approved for severe IGF-1 deficiency, the LR3 variant has not been approved for any medical use and remains a research compound. It is widely used in cell culture research to promote cell growth and survival due to its extended activity.,In research and performance enhancement contexts, IGF-1 LR3 is used for its potent anabolic and anti-catabolic properties. It promotes muscle hyperplasia (new muscle cell formation) in addition to hypertrophy (enlargement of existing cells), which distinguishes it from most other anabolic agents. However, its potent mitogenic activity raises theoretical concerns about promoting growth of pre-existing tumors.
Post-workout injection at target muscle (IM). Pin alone. 4-6 week cycles max.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
Binds to IGF-1 receptors (IGF-1R) on muscle and other tissue cells, activating the PI3K/Akt/mTOR signaling pathway, which promotes protein synthesis, cell growth, and inhibits apoptosis (programmed cell death).,Reduced IGFBP binding allows IGF-1 LR3 to circulate freely and remain bioactive for 20-30 hours, compared to minutes for native IGF-1. This provides sustained receptor activation and enhanced anabolic signaling throughout the body.,Stimulates satellite cell activation and proliferation in skeletal muscle, promoting muscle hyperplasia (formation of new muscle fibers) in addition to the hypertrophy produced by standard anabolic stimuli.
Binds to IGF-1 receptors (IGF-1R) on muscle and other tissue cells, activating the PI3K/Akt/mTOR signaling pathway, which promotes protein synthesis, cell growth, and inhibits apoptosis (programmed cell death).,Reduced IGFBP binding allows IGF-1 LR3 to circulate freely and remain bioactive for 20-30 hours, compared to minutes for native IGF-1. This provides sustained receptor activation and enhanced anabolic signaling throughout the body.,Stimulates satellite cell activation and proliferation in skeletal muscle, promoting muscle hyperplasia (formation of new muscle fibers) in addition to the hypertrophy produced by standard anabolic stimuli.
What to expect
Days 1-7: Mild hypoglycemia possible after dosing. Muscle pumps may increase during training. No major visible changes yet.
Evidence
Interactions & stacking
What's safe to combine, and what belongs in a separate pin.
Keep separate
Pharmacokinetics
Storage. Store refrigerated at 2-8C. Reconstituted solution should be used within 28 days. Avoid freeze-thaw cycles. Use bacteriostatic water for reconstitution.
Regulatory status
Not approved for human use by the FDA or any regulatory agency. Research chemical only. Native IGF-1 (mecasermin/Increlex) is FDA-approved for severe primary IGF-1 deficiency in children.
Put it to work
Calculate, log & track
Open IGF-1 LR3 straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.
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The guide & community
The complete IGF-1 LR3 walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.
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