What is IGF-1 LR3?

IGF-1 LR3 (Insulin-Like Growth Factor-1 Long Arg3) is a synthetically modified form of human Insulin-like Growth Factor 1. The molecule contains 83 amino acids and differs from endogenous IGF-1 by replacing the third amino acid position with arginine (Arg3), as well as by an added 13-amino acid sequence in the N-terminal region. These structural changes are associated with a longer biological half-life and lower affinity for IGF-binding proteins. In scientific literature, IGF-1 LR3 has been primarily considered in the context of cell growth, differentiation, and the regulation of protein metabolism.

As a stabilized analogue of IGF-1, IGF-1 LR3 has been used in various experimental models to study its interaction with IGF-1 receptors and the activation of intracellular signaling pathways such as PI3K/Akt and MAPK/ERK. These mechanisms are linked to processes like protein synthesis, cell proliferation, tissue regeneration, and metabolic regulation. Due to its extended half-life, described in the range of approximately 20–30 hours, IGF-1 LR3 is often used as a model compound in studies on longer-lasting anabolic and cellular processes.

Observations for IGF-1 LR3

In published scientific and preclinical data, IGF-1 LR3 has been considered in connection with the following:

• Cell growth and differentiation – involvement in mitogenic and anabolic processes

• Protein synthesis – activation of signaling pathways related to hypertrophic mechanisms

• Tissue regeneration – experimental models related to muscles, tendons, and nervous tissue

• Insulin-like activity – influence on glucose and amino acid transport to cells

• Studies on metabolic regulation and glucose homeostasis

• Neuroprotective mechanisms – potential role in maintaining neuronal structure and survival

Administration and Dosage

In scientific literature, experimental quantities in the range of 20–100 μg daily are found, used in controlled research settings. IGF-1 LR3 is primarily considered in short-term experimental models aimed at evaluating cellular proliferation, anabolic activity, and receptor-mediated signaling.

For 1 mg + 3 ml bacteriostatic water:

Concentration = 0.33 mg/ml → 0.06 ml = 20 μg

Approximate values:

0.06 ml = 20 μg

0.15 ml = 50 μg

0.3 ml = 100 μg

For 2 mg + 3 ml bacteriostatic water:

Concentration = 0.66 mg/ml → 0.06 ml = 40 μg

Approximate values:

0.06 ml = 40 μg

0.15 ml = 100 μg

0.3 ml = 200 μg

Scientific Data

IGF-1 LR3 has been the subject of preclinical and limited experimental research as a long-acting analog targeting the IGF-1 receptor system.

• In cellular models, activation of the PI3K/Akt signaling pathway and increased protein synthesis in myocytes have been described

• In experimental conditions, stimulation of hypertrophic processes and reduction of proteolysis have been observed

• In neuronal cultures, IGF-1 LR3 is associated with improved cell survival

• In tissue models related to injury and recovery, its potential to accelerate regenerative processes has been studied

• Its mechanism is not related to an increase in GH, but to direct interaction with IGF-1 receptors

Application in Sports and Research Settings

IGF-1 LR3 is included in the WADA list as a prohibited substance due to its potential anabolic effect. In laboratory and academic settings, the compound is used as a tool to study cell growth, protein metabolism, and signaling cascades related to IGF-1 receptor activity.

• A model for studying anabolic mechanisms without directly increasing GH

• Studies on muscle regeneration and recovery processes after tissue damage

• Research on metabolic regulation, insulin signaling, and nutrient substrate transport

Possible Side Effects

In the available scientific literature, IGF-1 LR3 is generally described as well-tolerated within experimental conditions. Transient and dose-dependent reactions have been noted:

• Local redness or discomfort at the site of experimental application

• Mild fatigue or drowsiness

• Headache or feelings of weakness at higher experimental quantities

• Reduction in blood sugar in sensitive models or individuals

The described reactions are predominantly transient and depend on the quantity and study conditions. No severe adverse reactions have been reported in published data for controlled research applications.

The information is based on scientific literature and is for educational purposes. It does not constitute medical advice and is not intended for diagnosis, treatment, prevention, or use in humans or animals.