IGF1 LR3

IGF-1 LR3 Peptide — Comprehensive Overview

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Insulin-like growth factor 1 LR3

Introduction

IGF-1 LR3 (Insulin-Like Growth Factor 1 Long Arg3) is a synthetic analogue of human insulin-like growth factor 1 (IGF-1) — a naturally occurring protein that plays a central role in cell growth, tissue repair, and muscle development.
The “LR3” modification extends its half-life, making it more stable and bioactive for research purposes.

As a result, IGF-1 LR3 peptide has become a major focus in muscle biology, recovery, and metabolic research, offering scientists a reliable tool for studying anabolic signaling and cell regeneration.

What Is IGF-1 LR3?

IGF-1 LR3 is a 83-amino acid peptide that differs from natural IGF-1 by substituting an arginine (Arg) at position 3 and adding a 13-amino-acid N-terminal extension.
These structural modifications significantly reduce its binding to IGF-binding proteins (IGFBPs) — allowing IGF-1 LR3 to remain active longer and interact more effectively with its receptor.

Chemical Information:

  • Synonyms: Long Arg3 IGF-1, IGF-1 Long R3
  • CAS Number: 946870-92-4
  • Molecular Formula: C₄₀₀H₆₂₅N₁₁₁O₁¹⁵S₉
  • Molecular Weight: 9117.5 g/mol
  • Sequence: MFPAMPLLSL…GIVEECCFRS (83 amino acids)
  • Form: Lyophilized powder
  • Purity: >98% (HPLC tested)

How IGF-1 LR3 Works

IGF-1 LR3 acts through the IGF-1 receptor (IGF-1R) — a transmembrane tyrosine kinase receptor found in muscle, liver, and other tissues.
When activated, it triggers the PI3K/Akt and MAPK signaling pathways, which regulate:

  • Protein synthesis and cell growth
  • Muscle fiber repair and hypertrophy
  • Cell survival and regeneration

Because IGF-1 LR3 has reduced affinity for IGFBPs, it remains unbound and biologically active longer than native IGF-1, making it a valuable compound for studying prolonged anabolic signaling.

Potential Research Applications

Although IGF-1 LR3 peptide is for research use only, it has become an important tool for investigating a wide range of biological functions:

  1. Muscle Growth and Regeneration Studies
    Used in controlled environments to study myoblast differentiation, satellite cell activation, and tissue recovery mechanisms.
  2. Cellular Growth and Repair Models
    IGF-1 LR3 supports research into cell proliferation, tissue regeneration, and growth factor signaling.
  3. Metabolic and Insulin Pathway Research
    Due to its close relation to insulin, IGF-1 LR3 helps researchers study glucose metabolism, energy utilization, and endocrine balance.
  4. Neuroprotective and Cognitive Function Studies
    Emerging data suggest IGF-1 analogues may support neuronal survival and synaptic plasticity, providing potential insights into neurobiology and aging.

Scientific Studies and Research

IGF-1 LR3 has been widely studied since its synthesis, with research demonstrating potent effects on cell signaling, muscle growth, and recovery in experimental models.

  • Frost et al., 2002 – Demonstrated enhanced muscle hypertrophy and recovery response following IGF-1 analog administration.
  • Yang et al., 2015 – Explored IGF-1R activation in cell-growth and anti-apoptotic pathways.
  • LeRoith & Yakar, 2019 – Identified IGF-1 as a critical regulator of metabolism, longevity, and cellular maintenance.

In laboratory contexts, these findings have positioned IGF-1 LR3 as one of the most versatile tools for understanding growth factor signaling and tissue regeneration.

Potential Risks and Safety Considerations

IGF-1 LR3 is supplied strictly for research and laboratory use.
It is not approved for human or veterinary applications.
Due to its strong interaction with growth pathways, all experiments should be performed in controlled settings by qualified personnel.

Improper handling may alter results or introduce biological variability — so strict adherence to laboratory standards is essential.

Summary

IGF-1 LR3 peptide represents one of the most studied and impactful compounds in growth factor and muscle regeneration research.
By extending IGF-1’s biological activity and receptor interaction window, it enables deeper investigation into anabolic signaling, tissue repair, and metabolic control.

Its use in laboratory settings continues to expand scientific understanding of cell growth, repair mechanisms, and the molecular basis of regeneration.

References

  • Frost, R. A. et al. “IGF-1 Mediated Muscle Growth and Recovery.” Am. J. Physiol. (2002).
  • Yang, Y. et al. “IGF-1 Receptor Signaling in Cell Survival and Growth.” J. Cell Sci. (2015).
  • LeRoith, D., & Yakar, S. “The Role of IGF-1 in Health and Disease.” Nature Reviews Endocrinology (2019).

Final Note

IGF-1 LR3 peptide is intended for research use only.
Not approved for human consumption or medical use.
For high-purity IGF-1 LR3 and other research peptides, visit our Research Peptide Shop.
You can also explore more insights in our Peptide Research Blog.