IGF-1 LR3 is a synthetic 83-amino acid analog of human insulin-like growth factor-1 (IGF-1) that has been structurally modified to enhance its biological activity. The 'LR3' designation refers to two key modifications: an arginine substitution at position 3 (replacing glutamic acid) and a 13-amino acid N-terminal extension peptide. These modifications dramatically reduce binding to IGF binding proteins (IGFBPs), resulting in a significantly longer half-life and greater bioavailability compared to native IGF-1. In research settings, IGF-1 LR3 demonstrates approximately 2-3 times greater potency than native IGF-1 in stimulating cellular proliferation, making it a valuable tool for studying growth factor biology, muscle development, and metabolic regulation.
Quickstart Highlights
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified analog of human IGF-1 with significantly extended half-life, studied for its anabolic and metabolic effects[1]. This synthetic variant exhibits reduced binding to IGF binding proteins, allowing enhanced bioavailability and systemic activity[2].
Storage Instructions
Proper storage is critical to maintain peptide stability and potency.
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Lyophilized (unopened): Store at −20 °C (−4 °F) or colder (−80 °C optimal) in dry, dark conditions for up to 12 months[4]; short-term storage at 2–8 °C (35.6–46.4 °F) for several months is acceptable.
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Reconstituted solution: Refrigerate at 2–8 °C (35.6–46.4 °F) immediately after mixing; use within 30 days for optimal potency[9].
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Extended storage of reconstituted solution: For storage beyond 30 days, prepare sterile aliquots and freeze at −20 °C (−4 °F); aliquots remain stable for 3–6 months[4]. Never refreeze a thawed vial.
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Handling: Allow frozen vials to reach room temperature before opening to minimize condensation; always inspect solution for clarity (discard if cloudy or contains particles)[10].
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Protection: Keep all vials protected from light and maintain cold chain during storage.
How It Works
IGF-1 LR3 is a synthetic analog of human insulin-like growth factor-1 engineered with an N-terminal extension (13 amino acids) and a glutamic acid substitution at position 3, resulting in significantly reduced binding affinity to IGF binding proteins[1]. This modification extends the peptide’s half-life from minutes (native IGF-1) to several hours and enhances systemic bioavailability[2].
The extended circulation time allows for once-daily administration protocols in research settings. Unlike native IGF-1, which requires frequent dosing, IGF-1 LR3 maintains more stable plasma levels throughout the day[11]. The peptide exhibits anabolic and metabolic activities through IGF-1 receptor binding, though it has never been approved for therapeutic human use and remains confined to research applications[12].
Studies examining IGF-1 and its analogs demonstrate effects on cellular growth, protein synthesis, and metabolic regulation. The insulin-like properties of IGF-1 LR3 necessitate careful attention to blood glucose management, particularly during initial dosing and titration phases[6].
Potential Benefits & Side Effects
Observations from preclinical and clinical literature on IGF-1 and its analogs.
Potential Research Observations:
- Enhanced anabolic signaling and protein synthesis in target tissues[1].
- Extended bioavailability compared to native IGF-1 due to reduced binding protein interaction[2].
- Metabolic effects through IGF-1 receptor pathways.
Important Safety Considerations:
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Hypoglycemia risk: The most significant concern with IGF-1 LR3 is its insulin-like effect on blood glucose; symptoms may include shakiness, confusion, sweating, or dizziness[6]. Always administer with food and monitor for glucose-related symptoms.
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No FDA approval: IGF-1 LR3 has never received regulatory approval for human therapeutic use and is restricted to research applications[12].
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Injection site reactions: Mild local irritation, redness, or discomfort may occur; proper technique and site rotation minimize these effects[8].
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Dose-dependent effects: Safety concerns increase substantially at doses exceeding 50–60 mcg/day; conservative dosing protocols are strongly recommended[2].
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Receptor desensitization: Continuous use beyond 6–8 weeks may lead to diminished response; cycling protocols (e.g., 8 weeks on, 4–8 weeks off) are commonly employed[7].
Lifestyle Factors
Complementary strategies to support research protocol outcomes.
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Nutrition: Maintain adequate protein intake (1.6–2.2 g/kg body weight) to support anabolic processes; ensure regular meal timing to manage blood glucose stability.
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Training: Combine resistance training protocols with appropriate recovery periods; IGF-1 signaling pathways are activated by mechanical loading.
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Sleep & Recovery: Prioritize 7–9 hours of quality sleep nightly to optimize endogenous growth factor production and tissue repair processes.
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Hydration: Maintain consistent hydration status to support metabolic function and peptide distribution.
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Glucose monitoring: Consider periodic blood glucose checks during dose titration, especially if experiencing any hypoglycemic symptoms.
References
