IGF-1 LR3 | The Long-Acting Insulin-Like Growth Factor

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a synthetic, highly potent analog of human IGF-1. It is engineered with a specific modification: the substitution of Glutamic Acid for Arginine at the third position and an additional 13-amino acid extension at the N-terminus. This alteration significantly reduces its affinity for IGF-binding proteins (IGFBPs), which normally inhibit IGF-1 activity. As a result, IGF-1 LR3 has a much higher biological activity and a vastly extended half-life (approximately 20–30 hours) compared to standard IGF-1.

Mechanism of Action

IGF-1 LR3 functions as a primary driver of cellular proliferation and hyperplasia:

• IGF-1 Receptor Activation: It binds to the IGF-1 receptor (IGF-1R), triggering the PI3K-Akt signaling pathway, which is the body's most critical pathway for muscle protein synthesis and cell survival.

• Hyperplasia Induction: Unlike many other anabolics that only cause hypertrophy (size increase of existing cells), IGF-1 LR3 is researched for its ability to induce hyperplasia—the splitting and creation of entirely new muscle cells.

• IGFBP Evasion: Because it does not bind well to inhibitory proteins, it remains "free" and active in the bloodstream for much longer periods, allowing for systemic tissue repair.

• Glucose Transport: It mimics insulin by increasing glucose uptake into the muscle cells, providing the necessary fuel for rapid growth and recovery.

Fitness & Recovery Research Benefits

In performance and regenerative research, IGF-1 LR3 is studied for its unique "permanent" growth signaling:

• New Muscle Fiber Development: It is the primary subject for research involving the bypass of genetic muscle limits through the creation of new fibers.

• Enhanced Nutrient Partitioning: Research indicates a profound ability to shuttle amino acids and carbohydrates into muscle tissue while inhibiting their transport into fat cells.

• Rapid Injury Rehabilitation: Due to its systemic nature and long half-life, it is investigated for its ability to heal connective tissue, nerves, and muscle tears more rapidly than natural recovery allows.

• Anti-Catabolic Effects: It effectively suppresses proteolysis (muscle protein breakdown), making it a high-interest compound for researching the maintenance of mass during periods of extreme physical stress.

• Synergy with Growth Hormone: While GH stimulates the liver to produce IGF-1, research often explores the direct administration of LR3 to provide a more targeted and sustained anabolic response.

Technical Specifications

• Sequence: 83 Amino Acid analog of human IGF-1

• Molecular Formula:

  $$C_{400}H_{625}N_{111}O_{115}S_{9}$$

• Storage: Store at -20°C for long-term stability. Once reconstituted, it is highly fragile; keep refrigerated and avoid shaking the vial.