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IGF-1 LR3

Insulin-like Growth Factor 1 LR3 · Long R3 IGF-1

IGF Axis & MusclePreclinical
From$32.49/mgCompare prices

Insulin-like Growth Factor 1 Long Arg3 (IGF-1 LR3) is a synthetic analog of the naturally occurring IGF-1 hormone, characterized by an extended amino acid sequence that enhances its binding affinity for the IGF-1 receptor while reducing its interaction with IGF-binding proteins. Researchers primarily study IGF-1 LR3 for its potential roles in promoting growth and development, particularly in fetal and postnatal contexts. Key findings from recent studies indicate that IGF-1 LR3 can stimulate cell proliferation and enhance axonal regeneration in nerve conduits, while other research suggests that its administration does not improve growth in growth-restricted fetal models despite altering amino acid concentrations. Current research is focused on optimizing IGF-1 LR3's applications in regenerative medicine and understanding its physiological effects in various developmental stages.

Chemical Profile

Chemical Profile

Half-Life

SCSubcutaneous

20-30 hours

IMIntramuscular

20-30 hours

POOral

Poor bioavailability

The extended half-life is due to reduced affinity for IGF-binding proteins.

Mechanism

Mechanism of Action

IGF-1 LR3 primarily exerts its effects through high-affinity binding to the IGF-1 receptor (IGF-1R), activating the insulin receptor substrate (IRS) signaling pathway, which subsequently stimulates the phosphoinositide 3-kinase (PI3K)/Akt pathway and the mitogen-activated protein kinase (MAPK) pathway. This activation promotes cellular processes such as proliferation, differentiation, and survival, particularly in fetal tissues, including cardiomyocytes and peripheral nerves. However, the complete mechanism of action, especially regarding its effects on insulin secretion and amino acid metabolism, remains not fully understood.

Research

13 Research Publications

270

Total Citations

1

Human/RCT

2.3

Avg. Influence

2025

Latest

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#01

Extracellular signal-regulated kinase and phosphoinositol-3 kinase mediate IGF-1 induced proliferation of fetal sheep cardiomyocytes.

AnimalInfluence4.0
127
The study demonstrated that IGF-1 LR3 stimulates cardiomyocyte proliferation in fetal sheep through ERK and PI3K signaling pathways without promoting hypertrophy.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#02

Insulin-like growth factor-1 (IGF-1) receptor-insulin receptor substrate complexes in the uterus. Altered signaling response to estradiol in the IGF-1(m/m) mouse.

Richards R G, et al. · The Journal of biological chemistry · 1998

Animal
49
Researchers studied how the hormone estradiol affects signaling pathways in the uterus of mice, specifically looking at the insulin-like growth factor-1 (IGF-1) receptor. They found that estradiol enhances the interaction between key proteins involved in cell growth, suggesting that these interactions play a significant role in how estradiol influences uterine function.

Key findings

  1. 01Researchers observed that estradiol stimulates the binding of insulin receptor substrate proteins to the IGF-1 receptor in the uterus.
  2. 02The study found that the absence of IGF-1 significantly weakens the signaling response to estradiol in the uterus.
  3. 03Researchers noted that estradiol decreases levels of IRS-2, indicating different roles for IRS-1 and IRS-2 in hormone signaling.
PubMed
#03

Involvement of insulin-like growth factor-1 and its binding proteins in proliferation and differentiation of murine bone marrow-derived macrophage precursors.

Long E, et al. · Endocrine · 1998

In Vitro
20
Researchers studied the role of insulin-like growth factor-1 (IGF-1) and its binding proteins in the development of immune cells called macrophages from bone marrow. They found that IGF-1 promotes the growth of these cells, but different forms of IGF-1 have varying effects on their maturation.

Key findings

  1. 01Researchers observed that the levels of IGF-1 increased as bone marrow-derived macrophages developed.
  2. 02The study found that different forms of IGF-1 influenced the proliferation and differentiation of macrophages in distinct ways.
  3. 03Researchers noted that the accumulation of IGFBP-4 might limit the effectiveness of IGF-1 during macrophage development.
PubMed
#04

IGF-1 infusion to fetal sheep increases organ growth but not by stimulating nutrient transfer to the fetus.

Stremming Jane, et al. · American journal of physiology. Endocrinology and metabolism · 2021

Animal
19
Researchers observed that LR3 IGF-1 infusion increased organ growth in late gestation fetal sheep without enhancing placental blood flow or nutrient transfer.

Key findings

  1. 01Researchers observed that IGF-1 infusion led to increased organ growth in fetal sheep.
  2. 02The study found that IGF-1 did not stimulate increased placental blood flow.
  3. 03Nutrient transfer from the placenta to the fetus was not improved by IGF-1 infusion.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#05

Action of long(R3)-insulin-like growth factor-1 on protein metabolism in beef heifers.

Hill R A, et al. · Domestic animal endocrinology · 1999

AnimalInfluence2.0
12
Researchers studied the effects of a specific insulin-like growth factor (Long(R3)-IGF-1) on protein metabolism in beef heifers that were losing weight due to limited feeding. They found that this treatment tended to preserve muscle and overall body protein, suggesting it could help reduce weight loss during challenging feeding conditions.

Key findings

  1. 01Long(R3)-IGF-1 infusion tended to conserve whole-body and skeletal muscle protein in beef heifers on a low-quality diet.
  2. 02The treatment significantly reduced plasma levels of amino acids and glucose in the heifers.
  3. 03Plasma concentrations of IGF-2 decreased dramatically in the treated group compared to the control group.
PubMed
#06

Coronary vascular growth matches IGF-1-stimulated cardiac growth in fetal sheep.

Jonker Sonnet S, et al. · FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2020

AnimalInfluence1.0
9
Researchers observed that IGF-1 LR3 treatment in fetal sheep preserved coronary conductance and function, supporting the expansion of coronary vasculature alongside increased myocardial growth.

Key findings

  1. 01Researchers found that IGF-1 treatment preserved coronary blood flow efficiency in relation to heart weight.
  2. 02The study observed that the mechanisms for blood vessel dilation during low oxygen levels were similar in both IGF-1-treated and control fetuses.
  3. 03Researchers concluded that IGF-1 stimulates both heart muscle and coronary blood vessel growth, suggesting its potential for improving heart development before birth.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#07

Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris.

Lu Zequn, et al. · Applied microbiology and biotechnology · 2023

Human
8
Researchers observed high recombinant expression of bioactive IGF-1 and LR3 IGF-1 in Pichia pastoris, achieving significant levels suitable for clinical and scientific applications.

Key findings

  1. 01Researchers observed that human IGF-1 and LR3 IGF-1 were successfully produced using the Pichia pastoris expression system.
  2. 02The purified IGF-1 and LR3 IGF-1 showed bioactivity comparable to standard IGF-1.
  3. 03High levels of these proteins were achieved through fermentation in a bioreactor, reaching significant concentrations.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#08

Reduced glucose-stimulated insulin secretion following a 1-wk IGF-1 infusion in late gestation fetal sheep is due to an intrinsic islet defect.

Animal
7
The study demonstrated that IGF-1 LR3 infusion reduced insulin concentrations and glucose-stimulated insulin secretion in fetal sheep, indicating an intrinsic islet defect.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#09

Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice.

Engel Matthew G, et al. · Journal of Alzheimer's disease : JAD · 2025

Animal
7
Researchers observed that intranasal LR3-IGF-1 treatment improved amyloid plaque remodeling in the cortex of male 5XFAD mice but did not preserve cognitive function.

Key findings

  1. 01LR3-IGF-1 treatment improved body composition in male 5XFAD mice.
  2. 02The treatment reduced filamentous amyloid plaques and increased inert plaques in the brain.
  3. 03Despite these changes in brain pathology, LR3-IGF-1 did not preserve cognitive function or memory.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
#10

N-Linked Glycosylation in Chinese Hamster Ovary Cells Is Critical for Insulin-like Growth Factor 1 Signaling.

Salvi Rupashree, et al. · International journal of molecular sciences · 2022

Animal
6
The study demonstrated that N-linked glycosylation is critical for IGF-1 signaling in CHO cells, affecting the abundance of IGF-1R and downstream signaling.

Key findings

  1. 01Researchers observed that N-glycans on cell surface proteins are essential for proper signaling of insulin-like growth factor 1.
  2. 02The study highlighted that disruptions in glycosylation can lead to changes in cell behavior and may be linked to various diseases.
  3. 03Findings suggest that understanding glycosylation could provide insights into disease mechanisms and potential therapeutic targets.
6.6 µg·kg-1·h-1infusion(fetal sheep)1 week1.17 ± 0.12 μg·kg-1·h-1infusion(fetal sheep)1 week3.260 ± 0.211 kgnot mentioned(fetal sheep)not mentioned3.682 ± 0.183not mentioned(fetal sheep)not mentioned
PubMed
Safety

Safety & Handling

Research Gaps

No clinical trials involving human subjects have been conducted to evaluate the efficacy and safety of IGF-1 LR3 for treating fetal growth restriction or other conditions. Additionally, the long-term effects of IGF-1 LR3 treatment on insulin secretion and glucose metabolism in both fetal and postnatal stages remain unclear, as well as the underlying mechanisms by which IGF-1 LR3 influences amino acid utilization and its impact on fetal growth.

Solubility

IGF-1 LR3 is soluble in water and aqueous buffers.

Storage & Handling

Lyophilized

Stable for 2+ years at -20°C, 12 months at 4°C

Reconstituted

Use within 14 days when refrigerated at 4°C

Avoid

Avoid repeated freeze-thaw cycles, direct light

Solvent

Bacteriostatic water or sterile saline recommended

Safety information is derived from published research and may not reflect all known risks. This is not medical advice.

Legal Status

Legal Status

🇩🇪DE

Not approved as a medicinal product. Not a controlled substance. Sale as research chemical is a legal grey area.

🇺🇸US

Not approved by the FDA for human use. Not scheduled by the DEA.

🇦🇺AU

Not approved by the TGA for therapeutic use.

🇬🇧UK

Not approved by the MHRA for medicinal use.

Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.

Community Insights

Community Insights

Publications per Year

11 total
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Mechanism

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Mechanism

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Legal Disclaimer

This page is for informational and research purposes only. All information is based on published scientific literature and does not constitute medical advice, diagnosis, or treatment recommendations. Many substances listed may not be approved for human use and may be subject to drug regulation laws (e.g., AMG in Germany, FDA in the US). PepStack does not encourage the use of any substance on humans. Always consult a qualified healthcare professional before making any health-related decisions. Use of this information is entirely at your own risk. PepStack assumes no liability for the accuracy, completeness, or timeliness of the content provided. Full disclaimer