IGF-1LR3 For Lab Research

IGF-1 LR3 Peptide | Buy IGF-1 LR3 UK | Long Arginine 3 IGF-1 Analogue | Research Use Only

IGF-1 LR3 (Long Arginine 3 IGF-1) is a synthetic 83-amino acid analogue of human Insulin-like Growth Factor-1, engineered with an N-terminal 13-amino acid extension and a Glu3→Arg3 substitution that dramatically reduces binding to IGF-binding proteins (IGFBPs), extends half-life to 20–30 hours, and increases in vivo potency approximately three-fold versus native IGF-1 — making it one of the most widely used and thoroughly characterised IGF-1 analogues in pre-clinical and cell biology research today. Buy IGF-1 LR3 in the UK from Peptides Lab UK with >99% HPLC-verified purity, batch-specific COA, and fast UK dispatch for laboratory and in vitro research use only.

Distributed by Peptides Lab UK in a high-purity lyophilised format, for laboratory research use only. This compound is handled in controlled settings for in vitro and pre-clinical studies, with no applications in human or veterinary medicine. Each batch undergoes rigorous quality analysis to ensure >99% purity (HPLC verified).

What Is IGF-1 LR3?

IGF-1 LR3 (Long Arginine 3-IGF-1) is a synthetic protein and lengthened analogue of human insulin-like growth factor-1. It differs from native IGF-1 in that it possesses an arginine instead of a glutamic acid at the third position in its amino acid sequence, and also has an additional 13 amino acids at its N-terminus (MFPAMPLLSLFVN), for a total of 83 amino acids relative to the 70 of native IGF-1.

The consequences of these modifications are that IGF-1 LR3 retains the pharmacological activity of IGF-1 as an agonist of the IGF-1 receptor, has very low affinity for the insulin-like growth factor-binding proteins (IGFBPs), and has improved metabolic stability — resulting in approximately three times greater potency than IGF-1, with a significantly longer half-life of about 20–30 hours relative to IGF-1’s half-life of about 12–15 hours.

The six IGFBPs serve as carrier proteins that bind approximately 98% of all circulating native IGF-1, with binding affinity equal to or greater than that of the IGF-1 receptor itself — meaning the vast majority of native IGF-1 is sequestered before reaching its receptor. IGF-1 LR3’s markedly reduced IGFBP affinity allows researchers to study sustained, IGFBP-independent IGF-1R signalling in a way that is not practically achievable with native IGF-1.

As a research compound, IGF-1 LR3 UK is one of the most broadly applied growth factor analogues in modern cell biology, with established use spanning myogenic research, stem cell culture maintenance, biopharmaceutical manufacturing models, and metabolic pathway investigation.

How Does IGF-1 LR3 Work?

IGF-1 LR3 functions through direct, sustained agonism of the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase, activating the same downstream intracellular signalling cascades as native IGF-1 — but with substantially reduced IGFBP-mediated attenuation and a far longer biological activity window.

The Two Structural Modifications and Their Research Significance

Analogues with substitutions, deletions, or insertions at the N-terminal end of native IGF-1 were found to reduce binding to IGFBPs and increase bioavailability to IGF-1R on cells — a principle exploited in the design of LR3, where the arginine substitution and N-terminal extension together confer superior IGFBP evasion compared to shorter analogues such as Arg3 IGF-1, Gly3 IGF-1, and Des(1-3) IGF-1.

IGF-1R Binding and Downstream Signalling

IGF-1 LR3 remains a full agonist of the IGF-1 receptor, with very low affinity for IGFBPs — making it more potent than unmodified IGF-1 in cell culture and pre-clinical models. IGF-1R is linked to various cytoplasmic second messenger molecules including the RAS-MAPK and PI3K signalling networks.

PI3K/Akt/mTOR and MAPK/ERK Pathway Activation

In research settings, IGF-1 LR3 activates the PI3K/Akt pathway (involved in survival, glucose metabolism, and protein synthesis), the RAS/MAPK pathway (regulating growth and differentiation), the mTOR pathway (governing anabolic protein synthesis signalling), and IRS-1/2 cross-talk with insulin receptor signalling — the full complement of IGF-1R-mediated downstream effects.

Extended Half-Life and Sustained Receptor Engagement

The 13-amino acid N-terminal extension and Arg3 substitution reduce IGFBP binding by 70–80%, extending the effective half-life from approximately 10 minutes to 20–30 hours in rodent plasma — resulting in prolonged IGF-1R activation in cell culture and animal models that is not achievable with native IGF-1 or shorter analogues.

What Does IGF-1 LR3 Do in Research?

In laboratory settings, IGF-1 LR3 has been studied across a remarkably broad range of biological systems. Research has examined its role in:

• IGFBP-independent, sustained IGF-1R activation and downstream pathway modelling
• Myogenic satellite cell proliferation, myotube formation, and skeletal muscle biology
• PI3K/Akt/mTOR and MAPK/ERK signalling cascade investigations
• Human pluripotent stem cell (hPSC) and embryonic stem cell (ESC) maintenance culture
• Mesenchymal stem cell niche biology and self-renewal pathway studies
• Biopharmaceutical CHO cell culture supplementation and recombinant protein production models
• Glucose uptake and GLUT4 translocation research in adipocyte models
• Vascular smooth muscle cell biology and plaque stability research
• Neuroregeneration, neuron survival, and peripheral nerve research applications models
• Protein synthesis, cellular hypertrophy, and anti-apoptotic pathway research

IGF-1 LR3 and Myogenic Research

Animal studies investigate skeletal muscle tissue responses to IGF-1 LR3 administration, with laboratory models measuring satellite cell activation via proliferation markers such as Ki-67, myotube formation and differentiation in vitro, and fibre cross-sectional area changes in mouse models — with research focusing on both hypertrophy and hyperplasia pathways.

IGF-1 LR3 and Stem Cell Culture Research

IGF-1 LR3 binds to the IGF-1 receptor and is a potent activator of the PI3K/AKT pathway and ERK1/2 signalling, and has been shown to be required for human pluripotent stem cell maintenance in the absence of insulin, as well as stimulating differentiation and proliferation of myeloid cells alongside IL-3 and regulating lymphopoiesis by supporting T and B cell development in lymphoid organs.

IGF-1 LR3 and Biopharmaceutical Cell Culture Research

Research conducted in industrially relevant CHO DP12 cell lines found that cells adapted to LONG R³ IGF-1 supplementation produced a twofold increase in recombinant protein yield compared to non-adapted cells, with a 40% increase in antibody titer versus insulin supplementation and a 62% increase relative to no growth factor — findings that have informed its widespread adoption in serum-free biopharmaceutical manufacturing models.

IGF-1 LR3 and Glucose Metabolism Research

In differentiated 3T3-L1 adipocytes, IGF-1 LR3 was used to investigate IGFBP-independent IGF-1R-mediated glucose uptake pathways, with research confirming that its effects on glucose transport are mediated directly through the IGF-1 receptor rather than through IGFBP modulation — providing a clean experimental tool for dissecting receptor-specific metabolic signalling.

What Do Studies Say About IGF-1 LR3?

IGF-1 LR3 has been characterised in peer-reviewed research since the early 1990s, with published studies spanning receptor biology, cell culture, skeletal muscle, stem cell science, and biopharmaceutical production.

IGF-1 LR3 Potency and Pharmacological Profile

Research has demonstrated that both IGF-1 and IGF-1 LR3 exhibit robust bioactivity at the IGF-1 receptor, with IGF-1 LR3 showing superior cell proliferation effects attributable to its reduced IGFBP sequestration — with the study concluding that IGF-1 LR3 holds considerable promise for scientific applications, particularly due to its prolonged receptor availability.

IGF-1 LR3 and the IGFBP Regulatory System

Structural analysis confirmed that among the series of N-terminal IGF-1 analogues tested, Long Arg3 IGF-1 demonstrated the greatest growth-promoting potential — exceeding shorter analogues such as Arg3 IGF-1, Gly3 IGF-1, and Des(1-3) IGF-1 — directly correlating with its superior IGFBP evasion profile.

IGF-1 LR3 in Stem Cell Self-Renewal Research

Research has established that IGF-1 receptor signalling is necessary for human embryonic stem cell self-renewal, and that IGF-1 LR3 can substitute for native IGF-1 in stem cell cultures with increased potency and stability — requiring lower concentrations for equivalent or superior biological effects compared to unmodified IGF-1.

IGF-1 LR3 in Anabolic and Dexamethasone-Treated Models

Tomas FM et al. (1992, Biochem J) demonstrated that IGF-1 and its variants — including Long R3 IGF-1 — are anabolic in dexamethasone-treated rats, confirming the utility of IGF-1 LR3 in models of catabolic states and muscle wasting where native IGF-1 activity is suppressed by glucocorticoid-driven IGFBP upregulation.

Key cited studies:

• Tomas FM et al. (1992) — IGF-1 and Especially IGF-1 Variants Are Anabolic in Dexamethasone-Treated Rats — Biochem J 282:91–97. DOI: 10.1042/bj2820091
• Youssef A et al. (2017) — The Roles of Insulin-Like Growth Factors in Mesenchymal Stem Cell Niche — Stem Cells Int. PMC5467583. DOI: 10.1155/2017/9453108
• Wamaitha SE et al. (2020) — IGF1-Mediated Human Embryonic Stem Cell Self-Renewal Recapitulates the Embryonic Niche — Nat Commun 11(1):764. DOI: 10.1038/s41467-020-14629-x
• Assefa B et al. (2017) — IGFBP-2 and IGF-1 LR3 in GLUT-4 Translocation in 3T3-L1 Adipocytes — Oxid Med Cell Longev. PMC5750484
• Thomas JN et al. — Comparison of Long R3 IGF-1 with Insulin in the Support of CHO Cell Growth and Recombinant Protein Expression — Repligen Scientific Poster

IGF-1 LR3 vs Other IGF-1 Research Analogues

Feature	IGF-1 LR3	IGF-1 DES	Native IGF-1
Sequence	83 aa (extended + Arg3 substitution)	67 aa (N-terminal truncated)	70 aa (full native sequence)
IGFBP Binding Reduction	~70–80% lower than native	~90–95% lower than native	Reference (98% bound)
Receptor Potency	~3x native IGF-1	~10x native IGF-1 (in vivo)	Reference
Half-Life	20–30 hours	~20–30 minutes	~10 min (free)
Activity Profile	Prolonged, systemic	Rapid, localised	Short, systemic
Cell Culture Use	Widely validated (CHO, stem cells)	Less established	Standard reference
Primary Research Use	Sustained GF signalling, stem cells, bioproduction	Localised receptor activation	IGF-1 baseline studies

IGF-1 LR3’s combination of prolonged half-life, broad IGFBP evasion, full receptor agonism, and extensive published validation across diverse research models makes it the preferred IGF-1 analogue where sustained, systemic IGF-1R engagement is the experimental objective.

Quality & Purity Assurance

Every batch of IGF-1 LR3 from Peptides Lab UK is:

• >99% pure — HPLC and mass spectrometry verified
• Supplied with a full Certificate of Analysis (COA) on request
• Lyophilised powder for maximum stability and long shelf life
• Manufactured under strict, controlled laboratory conditions
• Consistent batch-to-batch quality for reproducible research results

Buy IGF-1 LR3 UK — Product Specifications

Property	Detail
Full Name	Long Arginine 3 Insulin-like Growth Factor-1
Molecular Weight	~9,111 Da (9.1 kDa)
Amino Acids	83 (70 native IGF-1 sequence + 13 N-terminal extension)
Modifications	Glu3→Arg3 substitution; MFPAMPLLSLFVN N-terminal extension
Purity	>99% (HPLC verified)
Form	Lyophilised powder
Storage	Store dry at -20°C; protect from light
Solubility	Bacteriostatic water, sterile water, or suitable laboratory solvents

IGF-1 LR3 Research Applications

IGF-1 LR3 peptide UK is supplied strictly for the following in vitro and pre-clinical research uses:

• IGFBP-independent, sustained IGF-1R receptor binding and activation studies
• PI3K/Akt/mTOR and MAPK/ERK downstream signalling pathway research
• Myogenic satellite cell activation, proliferation, and differentiation investigations
• Human pluripotent stem cell (hPSC), ESC, and MSC culture maintenance research
• Biopharmaceutical CHO cell culture supplementation and recombinant protein production models
• Glucose uptake, GLUT4 translocation, and metabolic signalling research
• Vascular smooth muscle cell biology and atherosclerosis model studies
• Neuroregeneration, neuron survival, and peripheral nerve research applications research
• Protein synthesis, hypertrophy, and anti-apoptotic pathway investigations
• Comparative IGF-1 analogue structure–activity relationship (SAR) studies

Why Buy IGF-1 LR3 from Peptides Lab UK?

Peptides Lab UK is a trusted UK peptides supplier, providing research-grade compounds verified by independent HPLC testing. When you buy IGF-1 LR3 in the UK from us, you receive:

• >99% purity, HPLC and MS verified, third-party tested
• Full COA documentation per batch
• Fast same-day UK dispatch with tracked delivery
• Competitive pricing with bulk research discounts available
• Trusted by researchers across the UK and Europe

Research Disclaimer All products supplied by Peptides Lab UK are intended strictly for in vitro laboratory research and scientific study use only. They are not intended for human consumption, veterinary use, or any medical or therapeutic application. IGF-1 LR3 is not a licensed medicine or drug and has not been approved by the MHRA, FDA, or any regulatory authority for use in humans or animals. All research citations on this page relate to pre-clinical studies and peer-reviewed pharmacological research and do not constitute a claim of safety or therapeutic efficacy. Peptides Lab UK accepts no liability for any misuse of research compounds. By purchasing, you confirm that you are a qualified researcher and that the product will be used solely within a controlled laboratory environment in compliance with all applicable UK laws, regulations, and institutional guidelines.