How is IGF-1 different from IGF-1 LR3?

Native IGF-1 has a very short free half-life and is heavily bound by IGF-binding proteins. IGF-1 LR3 is an analog engineered to resist binding-protein sequestration, giving it a much longer active duration in research settings.

Why is IGF-1 associated with growth hormone?

Growth hormone exerts many of its anabolic effects indirectly by stimulating hepatic IGF-1 production, so IGF-1 is considered the downstream mediator of GH signaling.

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Muscle Growth

Research Chemical

IGF-1

Also known as: IGF-1, Insulin-like Growth Factor 1

IGF-1 is a 70-amino-acid peptide hormone that mediates most of the anabolic and growth-promoting effects of growth hormone. It is studied for muscle growth, tissue repair, and metabolic signaling.

Mechanism of Action

IGF-1 binds the IGF-1 receptor (IGF-1R), a transmembrane receptor tyrosine kinase, triggering autophosphorylation and recruitment of IRS-1 and Shc adaptor proteins. This activates the PI3K/Akt/mTOR pathway to drive protein synthesis and cell survival, and the Ras/MAPK pathway to drive proliferation. Circulating IGF-1 is largely produced in the liver under GH stimulation and is buffered by IGF-binding proteins (notably IGFBP-3) that modulate its half-life and bioavailability.

Half-life: Roughly 10-15 minutes free, but up to 12-16 hours when bound to IGFBP-3 in circulation
Administration Routes: subcutaneous
Research Status: Research Chemical