IGF-1 LR3

Why Researchers Choose IGF-1 LR3

IGF-1 LR3, the Long R3 analogue of Insulin-like Growth Factor 1, is studied wherever a long-acting, high-availability IGF-1 signal is needed to probe anabolic and regenerative biology. Because its 20 to 30 hour half-life keeps the IGF-1 receptor engaged far longer than native IGF-1, it is a common tool in:

• Muscle protein synthesis and hypertrophy signalling studies
• Satellite cell proliferation, differentiation and myonuclear-accretion research
• PI3K/Akt/mTOR pathway activation and ribosomal-biogenesis investigations
• Tissue repair, regeneration and anti-apoptotic survival models
• Glucose-uptake and nutrient-partitioning experiments in skeletal muscle

IGF-1R Signalling Cascade

IGF-1 LR3 binds the IGF-1 receptor (IGF-1R) with affinity comparable to native IGF-1. IGF-1R is a receptor tyrosine kinase, and once activated it propagates several downstream cascades.

PI3K/Akt/mTOR pathway:

• PI3K converts PIP2 to PIP3 at the membrane
• PIP3 recruits Akt (PKB) for activating phosphorylation
• Active Akt phosphorylates and activates mTORC1
• mTORC1 engages S6K1 and 4E-BP1, driving ribosomal biogenesis and cap-dependent protein translation

MAPK/ERK pathway:

• The Ras, Raf, MEK, ERK relay drives proliferative gene expression
• Promotes cell-cycle entry in satellite cells and other progenitors

Anti-apoptotic signalling:

• Akt phosphorylates and inactivates pro-apoptotic proteins such as Bad and caspase-9
• Supports cell survival during high-stress tissue remodelling

Satellite Cell Activation

The most consequential long-term growth mechanism runs through muscle satellite cells, the quiescent stem cells that sit beneath the basal lamina of skeletal muscle fibres. In response to IGF-1R stimulation these cells:

• Exit quiescence and proliferate
• Differentiate into myoblasts
• Fuse with existing fibres and donate new nuclei
• Allow each fibre to support a larger volume of contractile protein per added nucleus

This satellite cell response is what lets IGF-1 LR3 be associated with lasting increases in muscle fibre nuclear content, rather than only transient anabolic spikes.

IGF-1 LR3 vs GHRH/GHRP Protocols

Reconstitution and Storage

Reconstitution: the peptide is degradation-sensitive, so use 0.6% acetic acid solution rather than plain bacteriostatic water for optimal stability; swirl gently until dissolved, do not shake. After reconstitution: keep the solution refrigerated at 2-8°C and use within roughly three weeks.

For research purposes only. Not for human consumption.