Abstract The IGF-1 LR3 0.1mg peptide pen contains a highly specific, low-concentration solution of Long Arg3 Insulin-like Growth Factor-1. This recombinant analogue is chemically modified to include a 13-amino acid extension at the N-terminus and the substitution of Arginine for Glutamic acid at position 3. These structural modifications drastically reduce the peptide’s affinity for Insulin-like Growth Factor Binding Proteins (IGFBPs), which normally inhibit the biological action of native IGF-1. Consequently, IGF-1 LR3 exhibits a significantly extended half-life (approximately 20–30 hours compared to 20 minutes for native IGF-1) and enhanced potency. This 0.1mg (100mcg) formulation is specifically engineered for high-sensitivity applications, such as serum-free cell culture supplementation and micro-dosing in murine models of muscle hyperplasia.

Mechanism and Research Interest

Primary Biological Pathway: Evasion of IGFBPs

The defining research characteristic of IGF-1 LR3 is its inability to bind to IGFBPs. In a biological system, >98% of native IGF-1 is sequestered by these binding proteins, rendering it biologically inactive.

By evading this sequestration, IGF-1 LR3 remains available in the free fraction to bind and activate the Type 1 IGF Receptor (IGF-1R). Research utilising the 0.1mg pen focuses on quantifying this “free fraction potency,” specifically aiming to determine the proliferation rates of cell lines in media devoid of bovine serum.

Secondary Research Finding: Satellite Cell Proliferation (Hyperplasia)

IGF-1 LR3 is a potent mitogen. Unlike Growth Hormone, which primarily causes hypertrophy (increase in cell size), IGF-1 LR3 stimulates hyperplasia (increase in cell number) by activating satellite cells in skeletal muscle. The 0.1mg format allows for the delivery of precise microgram quantities to local tissue environments. Researchers utilise this to study the MyoD and Myogenin transcription factors, investigating the mechanism by which the peptide forces quiescent stem cells to enter the cell cycle and fuse with existing myofibers.

Tertiary Research Finding: Glucose Transport and Insulin Mimicry

Structurally homologous to pro-insulin, IGF-1 LR3 binds to the insulin receptor with lower affinity but high efficacy regarding glucose transport. It stimulates the translocation of GLUT4 transporters to the cell membrane. Current studies use the 0.1mg pen in metabolic assays to differentiate between the anabolic effects (protein synthesis via mTOR) and the metabolic effects (glucose uptake via PI3K/Akt) in insulin-resistant tissue models.

Long-term Genomic and Safety Observations

Genomic research into IGF-1 LR3 focuses on the “mitogenic risk.” Because it is a potent survival factor that inhibits apoptosis, there is theoretical concern regarding oncogenesis. Long-term studies utilising this low-dose formulation monitor the expression of tumour suppressor genes (p53, PTEN) in proliferative tissues. This data is vital for establishing the safety threshold for therapeutic use in muscle wasting diseases compared to systemic metabolic interventions.

Product Specifications

• Purity: Validated at >98+% via High-Performance Liquid Chromatography (HPLC) and SDS-PAGE. We ensure the correct folding of the three intramolecular disulfide bridges, which are critical for receptor recognition.

• Appearance: The 3ml pen contains a clear, colourless, sterile liquid.

• Precision: The pen delivery system is calibrated for micro-dosing. With a total load of only 100mcg, the pen allows for the administration of extremely small, potent doses (e.g., 5-10mcg), which is essential for small animal models (mice/rats) where overdose leads to severe hypoglycaemia.

• Storage: The product must be stored at 2∘C to 8∘𝐶.

Storage and Shipping Guidelines

Refrigeration and Shelf Life

The IGF-1 LR3 0.1mg Pen contains a potent growth factor that is highly sensitive to thermal denaturation. It must be refrigerated ($2^{\circ}C$ to $8^{\circ}C$). The shelf life is 12 months in the sealed state. Once the pen is accessed, the bacteriostatic environment preserves the solution for 28 days. Researchers should note that due to the very low protein concentration (33.3 $\mu g$/ml), the peptide is susceptible to adsorption to plastic surfaces; the pen cartridge is specially treated to minimise this loss.

Shipping Stability

We utilise medical-grade thermal packaging. The peptide is stable for up to 72 hours at ambient UK temperatures. However, given the low mass and high sensitivity of the recombinant protein, we strongly recommend selecting the fastest available shipping option.

Freezing Warning

Do not freeze. Freezing can disrupt the tertiary structure of the growth factor. In such a dilute solution, freeze-thaw cycles can cause significant loss of bioactivity due to aggregation and surface adsorption. A frozen pen should be discarded.

Why Choose the Peptide Pro 3ml Pen Format?

The IGF-1 LR3 0.1mg Pen is the specialized tool for High-Sensitivity and Cell Culture Research.

Most commercial IGF-1 is sold in larger milligram vials, which requires extensive dilution for use in murine models or cell assays. This dilution process introduces pipetting errors and sterility risks.

Our 0.1mg pen provides a pre-diluted, sterile, and stable source of the peptide. It allows for direct addition to culture media or direct micro-injection without the need for intermediate solvent handling, ensuring that the concentration interacting with your receptors is exactly what you calculated.

For researchers investigating the upstream regulation of growth factors, we recommend examining:

• MGF (Mechano Growth Factor) 2mg: (For research into the specific splice variant of IGF-1 involved in initial muscle repair).

• Ipamorelin 10mg:  (For stimulating endogenous GH/IGF-1 production).

Disclaimer

This product is strictly for Research Use Only (RUO). It is not intended for human consumption, injection (e.g., for bodybuilding or muscle enhancement), therapeutic use, or diagnostic procedures. The information provided is for educational and scientific reference only. Purchase is restricted to verified research institutions and qualified individuals. Any evidence of intended misuse for human application will result in immediate order cancellation and blacklisting, in compliance with UK research chemical regulations.