IGF-1 LR3 Peptide (Insulin-like Growth Factor-1 Long Arg3) – Research Grade

IGF-1 LR3 (Long Arginine 3 IGF-1) is a synthetic, 83-amino acid analog of human insulin-like growth factor-1 (IGF-1) engineered for enhanced biological stability and potency . The structure incorporates a glutamic acid-to-arginine substitution at position 3 (hence “R3”) and a 13-amino acid N-terminal extension peptide . This modification reduces the analog’s affinity for IGF-binding proteins (IGFBPs) by over 100-fold compared to native IGF-1, dramatically prolonging its half-life and bioavailability in vitro . With a half-life of approximately 20–30 hours, IGF-1 LR3 is significantly more potent than the regular IGF-1 base .

IGF-1 LR3 functions primarily through binding to the IGF-1 receptor (IGF1R), activating the PI3K/AKT and MAPK signaling pathways that stimulate cell growth, proliferation, and survival while inhibiting apoptosis . Research has explored its applications in diverse areas, including mammalian cell culture, neuroprotection, and Alzheimer’s disease research .

⚠️ Research Context: This product is intended exclusively for in-vitro and laboratory research purposes. It is not approved by the FDA for human use. All sources confirm: “FOR RESEARCH, LABORATORY AND MANUFACTURE USE ONLY. NOT INTENDED FOR DIRECT USE ON HUMANS” .

Mechanism of Action

IGF-1 LR3 functions as a highly potent ligand for the IGF-1 receptor (IGF1R) :

Enhanced Bioavailability:

• The arginine substitution at position 3 and N-terminal extension dramatically reduce binding to IGF-binding proteins (IGFBPs) 

• Free from the regulatory constraints of binding proteins, the analog remains active up to 120 times longer than standard IGF-1 

Receptor Activation & Signaling:

• Binds to the IGF1R alpha subunit, activating intrinsic tyrosine kinase activity and autophosphorylation of tyrosine residues in the beta subunit 

• Triggers downstream activation of the PI3K-AKT/PKB and Ras-MAPK signaling cascades 

• Stimulates cellular proliferation, differentiation, and protein synthesis 

Metabolic Effects:

• Promotes glucose uptake and glycogen synthesis in bone-derived cells 

• Regulates fat metabolism and can stimulate lipolysis 

Key Research Applications:

• Cell culture supplementation (serum-free or low-serum systems) 

• Cellular growth, proliferation, and differentiation studies 

• Signal transduction research (PI3K/AKT, MAPK pathways) 

• Protein synthesis and muscle cell hypertrophy assays 

• Neuroprotection and Alzheimer’s disease research 

Product Specifications

Quality Assurance

Every batch of IGF-1 LR3 undergoes rigorous analytical testing:

Certificate of Analysis (COA) available upon request.

Research Background

Structural Engineering & Enhanced Activity

IGF-1 LR3 was specifically engineered to overcome the limitations of native IGF-1 in research applications. Natural IGF-1 binds strongly to a family of IGF-binding proteins (IGFBPs) that regulate its bioavailability. By substituting arginine for glutamic acid at position 3 and adding an N-terminal extension, the LR3 analog exhibits >100-fold reduced affinity for IGFBPs, making it an ideal choice for studies requiring sustained receptor engagement . The analog’s enhanced half-life (20–30 hours)  and increased activity—estimated up to 120 times longer than standard IGF-1 —allow for reduced dosing frequency in cell culture models.

Key Research Findings

Neuroprotection & Alzheimer’s Disease (2024):
A 2024 study published in the Journal of Alzheimer’s Disease investigated intranasal LR3-IGF-1 treatment in male 5XFAD mice over 7 months. The treatment improved body composition and promoted favorable effects on Aβ plaque remodeling in the cortex, including a reduction in filamentous plaques and low molecular weight Aβ oligomers. In vitro, LR3 enhanced Aβ uptake by BV2 microglial cells and promoted gene pathways involved in actin remodeling and endocytosis. However, the study concluded that LR3 as a monotherapy failed to preserve cognitive function, suggesting that combinatorial formulations may be required .

Cell Culture Supplementation:
IGF-1 LR3 is widely adopted as a supplement in serum-free or low-serum cell culture systems to support cell viability, proliferation, and differentiation . Its prolonged activity and reduced degradation make it a reliable alternative to native IGF-1 for maintaining optimal cellular function over extended experimental timelines .

Signal Transduction:
The peptide is frequently employed to probe intracellular pathways involved in metabolism, apoptosis, and gene expression, offering insights into receptor specificity, ligand-receptor dynamics, and cross-talk with other growth factor systems .

Storage & Reconstitution Guidelines

Storage Conditions:

• Lyophilized (Long-term): ≤ -20°C, stable for at least 36 months 

• Reconstituted (Short-term): 2–8°C for up to 1 week 

• Reconstituted (Long-term): -20°C or -80°C with carrier protein (0.1% BSA, 5% HSA, or 10% FBS) 

• Avoid repeated freeze-thaw cycles 

Reconstitution Protocol:

1. Briefly centrifuge vial to bring contents to bottom

2. Reconstitute at 100–200 µg/mL in sterile water 

3. Gently swirl (do not vortex) until fully dissolved

4. Further dilutions can be made in other aqueous buffers

5. Aliquot immediately to avoid repeated freeze-thaw cycles 

Important Note: For long-term storage after reconstitution, the addition of a carrier protein (0.1% BSA, 5% HSA, or 10% FBS) is strongly recommended to maintain stability .

Important Notice

⚠️ FOR RESEARCH USE ONLY

This product is not intended for human consumption, diagnostic use, therapeutic application, or clinical administration. IGF-1 LR3 is a research-grade reagent intended exclusively for in-vitro and laboratory research purposes.

• Not approved by the FDA for human use

• Not a dietary supplement, food additive, or pharmaceutical for over-the-counter purchase

• Research-grade product — requires proper laboratory handling and training 

• Not for use in humans, animals, or in vitro diagnostic procedures 

By purchasing this product, you confirm that you are a licensed researcher or laboratory professional and agree to use this compound in compliance with all applicable local, national, and international regulations.

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IGF-1 LR3 Peptide – >95% Purity
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