IGF-1 LR3

Overview

IGF‑1 LR3 (Insulin‑like Growth Factor 1 Long Arg3) is a synthetic analog of endogenous IGF‑1 with an extended half‑life due to modifications at the N‑terminus and a substitution of arginine at position 3. These changes significantly reduce binding to IGF binding proteins, increasing bioavailability and duration of action. IGF‑1 is a potent growth factor involved in cellular proliferation, muscle protein synthesis, and tissue regeneration. LR3 is widely studied in preclinical and laboratory contexts for its extended activity profile.

Mechanism of Action (Research Context)

IGF‑1 LR3 acts primarily through the IGF‑1 receptor (IGF‑1R), a transmembrane tyrosine kinase receptor that activates PI3K/Akt and MAPK pathways. These pathways are crucial for cellular growth, differentiation, and survival. The LR3 modification extends its half‑life from minutes to approximately 20–30 hours, allowing for prolonged receptor activation. This peptide influences myogenesis, satellite cell proliferation, protein synthesis, and tissue repair mechanisms.

Potential Research Benefits (Reported in Literature)

• Muscle growth and repair: IGF‑1 LR3 is frequently studied for its role in stimulating satellite cells, promoting protein synthesis, and supporting muscle hypertrophy in preclinical models.

• Tissue regeneration: Research shows activity in supporting regenerative pathways in skeletal muscle, tendons, and other tissues.

• Enhanced recovery: Prolonged receptor activation has been associated with improved recovery time in models of injury and physical stress.

• Metabolic effects: IGF‑1 influences glucose uptake and insulin sensitivity pathways, making it relevant in metabolic research.

• Neuroprotective properties: Early data suggest IGF‑1 signaling may support neural growth and protection, including modulation of neuroinflammation and apoptosis in experimental settings.

Potential Reported Side Effects / Adverse Events

Reported effects from early human studies and observational contexts include transient hypoglycemia, headache, water retention, joint discomfort, and localized reactions. As IGF‑1 is a potent growth factor, prolonged or uncontrolled exposure may influence cellular proliferation and raise theoretical concerns regarding mitogenic effects. Formal safety and toxicology data remain incomplete.

Reported Findings / Key Points

• IGF‑1 LR3 is a long‑acting analog of IGF‑1 with reduced binding to IGF binding proteins, resulting in increased bioavailability.

• Strongly activates IGF‑1R signaling cascades involved in anabolic and regenerative pathways.

• Preclinical data indicate potential applications in muscle repair, tissue regeneration, and neuroprotection.

• Side effects primarily relate to insulin‑like actions, fluid balance, and mitogenic potential.

• No regulatory approval exists for therapeutic use.

Chemical / Physical Information

• Sequence: 83 amino acids with Arg substitution at position 3 (Long R3 modification) • Approximate molecular weight: ~9111 Da • Class: Synthetic IGF‑1 analog • General handling: store lyophilized at −20 °C, protect from light and moisture; aliquot reconstituted solutions and avoid repeated freeze–thaw cycles.

Notes on Formats Studied

IGF‑1 LR3 has been evaluated in research settings using injectable formulations. No approved human dosing exists. Preclinical protocols vary widely.

Regulatory & Compliance Notes

IGF‑1 LR3 is not approved for therapeutic use by any major health authority. It appears on the WADA Prohibited List under peptide hormones and growth factors. All procurement, storage, and research use must comply with relevant legal and institutional regulations.

References (Selection)

• Le Roith D, et al. 'Insulin‑like growth factors and their binding proteins.' Ann N Y Acad Sci. • Shavlakadze T, et al. IGF‑1 signaling in skeletal muscle regeneration. • Velloso CP. Regulation of muscle mass by IGF‑1 signaling pathways. • WADA Prohibited List — Peptide Hormones and Growth Factors.

Disclaimer

This is only intended for research purposes. None of this is intended for human consumption. This is only for educational and informational purposes.

----------------------------------

Selected References

PMID: 11397942 — IGF-1 LR3 analog activity and extended receptor signaling

PMID: 11875112 — IGF-1–mediated anabolic and regenerative pathways

PMID: 21636535 — Growth-factor signaling in muscle hypertrophy and repair

PMID: 25540140 — Peptide-based modulation of IGF-1 pathways and metabolic effects

Frontiers in Endocrinology — IGF-1 axis regulation and therapeutic applications

Journal of Peptide Science — Growth-factor peptides and anabolic mechanisms

Frequently Asked Questions (FAQ)

Q1: What is IGF-1 LR3?A1: IGF-1 LR3 is a long-acting analog of insulin-like growth factor-1, designed for extended receptor activity and used in research to study cellular growth, recovery, and metabolic pathways.

Q2: How does IGF-1 LR3 work in research studies?A2: IGF-1 LR3 binds to IGF-1 receptors and downstream signaling pathways such as PI3K-Akt and MAPK, influencing cellular growth, protein synthesis, and nutrient utilization.

Q3: Why is IGF-1 LR3 longer-acting than regular IGF-1?A3: IGF-1 LR3 contains a modified amino-terminal sequence and an extended chain length, reducing its binding to IGF-binding proteins and increasing biological half-life.

Q4: What do researchers study IGF-1 LR3 for?A4: Research explores IGF-1 LR3 in contexts such as muscle cell proliferation, tissue recovery, metabolic function, and cellular signaling efficiency.

Q5: Is IGF-1 LR3 approved for medical or consumer use?A5: No. IGF-1 LR3 discussed here is a research compound and is not approved for therapeutic or general consumer use.

Q6: How is IGF-1 LR3 evaluated in laboratory models?A6: Studies use in vitro cell assays and animal models to measure effects on protein synthesis, nutrient partitioning, growth signaling, and regenerative activity.

Q7: What side effects are reported in research models?A7: Research notes potential insulin-like activity and hypoglycemia-related responses in certain models, but comprehensive human safety is not established.

Related Research Compounds

• Tesamorelin

• BPC-157

• TB-500

• GHK-Cu

• Dihexa