IGF-1 Analog

IGF-1 LR3

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Overview

A modified insulin-like growth factor with reduced binding-protein affinity and a longer half-life, used widely in cell culture; human therapeutic use is not approved.

How it works

IGF-1 LR3 is a modified, longer-lasting version of insulin-like growth factor 1 (IGF-1), a hormone that drives cell growth and division. It's used mainly as a research reagent.

Two changes — a swapped amino acid and an added segment — reduce how tightly it sticks to the binding proteins that normally hold IGF-1 in check, leaving more of it free and active. Acting on the IGF-1 receptor, it switches on growth-promoting pathways (PI3K/Akt and MAPK) more potently and for longer than natural IGF-1.

That same potent growth signaling is a double-edged sword: it's the basis for anabolic interest but also a theoretical concern, since strong, sustained growth stimulation raises proliferative and cancer-related questions. It is not approved for human use.

Mechanism · Detailed Analysis

Molecular targetAn IGF-1 receptor (tyrosine-kinase) agonist; an Arg3 substitution and N-terminal extension lower its affinity for IGF-binding proteins, leaving more free peptide active.

Signaling & downstream effectsActivates PI3K/Akt and MAPK growth signalling, with longer action than native IGF-1.

Evidence & caveatsPrimarily a cell-culture reagent. The same growth signalling underlies both anabolic interest and a theoretical proliferative/oncologic concern; not approved for human use.

Published EvidenceFree · cited live from PubMed

Human Data 10

Study

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

Lu Z et al. · Applied microbiology and biotechnology · 2023 — PMID 37261455 ↗

Research Support, Non-U.S. Gov't

The role of IGFBP-3 in the regulation of IGFBP-4 proteolysis

Donnelly MJ et al. · The Journal of endocrinology · 1996 — PMID 8691093 ↗

Study

Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions

Robertson JG et al. · The American journal of physiology · 1999 — PMID 10198302 ↗

Research Support, Non-U.S. Gov't

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas FH et al. · Reproduction (Cambridge, England) · 2007 — PMID 17636166 ↗

Research Support, Non-U.S. Gov't

Enhanced response of granulosa and theca cells from sheep carriers of the FecB mutation in vitro to gonadotropins and bone morphogenic protein-2, -4, and -6

Campbell BK et al. · Endocrinology · 2006 — PMID 16396991 ↗

Research Support, N.I.H., Extramural

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Haluska P et al. · Cancer research · 2006 — PMID 16397250 ↗

Research Support, Non-U.S. Gov't

Potentiation of growth factor signaling by insulin-like growth factor-binding protein-3 in breast epithelial cells requires sphingosine kinase activity

Martin JL et al. · The Journal of biological chemistry · 2009 — PMID 19633297 ↗

Study

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 MG et al. · Journal of Alzheimer's disease : JAD · 2025 — PMID 39610283 ↗

Randomized Controlled Trial

Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells

Khamsi F et al. · Fertility and sterility · 2001 — PMID 11334915 ↗

Research Support, Non-U.S. Gov't

The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation

Pesall JE et al. · Poultry science · 2001 — PMID 11469659 ↗

Search this category on PubMed →

Animal 32

Study

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep

White A et al. · American journal of physiology. Endocrinology and metabolism · 2025 — PMID 39679943 ↗

Research Support, N.I.H., Extramural

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

White A et al. · Journal of developmental origins of health and disease · 2023 — PMID 37114757 ↗

Study

Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration

Yavuz E et al. · International journal of biological macromolecules · 2025 — PMID 41015370 ↗

Research Support, N.I.H., Extramural

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

Jonker SS et al. · FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2020 — PMID 32573852 ↗

Research Support, N.I.H., Extramural

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

Stremming J et al. · American journal of physiology. Endocrinology and metabolism · 2021 — PMID 33427051 ↗

Research Support, Non-U.S. Gov't

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

Levolger S et al. · Scientific reports · 2019 — PMID 31285507 ↗

Research Support, Non-U.S. Gov't

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

Sundgren NC et al. · American journal of physiology. Regulatory, integrative and comparative physiology · 2003 — PMID 12947030 ↗

In Vitro 20

Research Support, N.I.H., Extramural

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

White A et al. · Journal of developmental origins of health and disease · 2023 — PMID 37114757 ↗

Study

Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep

Stremming J et al. · Frontiers in physiology · 2022 — PMID 36091374 ↗

Research Support, Non-U.S. Gov't

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

Levolger S et al. · Scientific reports · 2019 — PMID 31285507 ↗

Research Support, N.I.H., Extramural

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Haluska P et al. · Cancer research · 2006 — PMID 16397250 ↗

Research Support, Non-U.S. Gov't

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

Sundgren NC et al. · American journal of physiology. Regulatory, integrative and comparative physiology · 2003 — PMID 12947030 ↗

Research Support, N.I.H., Extramural

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

White A et al. · American journal of physiology. Endocrinology and metabolism · 2021 — PMID 33938236 ↗

Research Support, Non-U.S. Gov't

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas FH et al. · Reproduction (Cambridge, England) · 2007 — PMID 17636166 ↗

Studies are surfaced live from the U.S. National Library of Medicine (PubMed). biohackr indexes and links the published record; it does not host or alter source articles.

Published EvidenceLoading cited studies from PubMed…

Human Data ···

Searching the published record…

Animal ···

Searching the published record…

In Vitro ···

Searching the published record…

Educational aggregation of public literature. Not medical advice and not a recommendation to use any compound. Many compounds here are not approved for human use. Consult a licensed clinician.

Published EvidenceFree · cited live from PubMed

Human Data 10

Study

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

Lu Z et al. · Applied microbiology and biotechnology · 2023 — PMID 37261455 ↗

Research Support, Non-U.S. Gov't

The role of IGFBP-3 in the regulation of IGFBP-4 proteolysis

Donnelly MJ et al. · The Journal of endocrinology · 1996 — PMID 8691093 ↗

Study

Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions

Robertson JG et al. · The American journal of physiology · 1999 — PMID 10198302 ↗

Research Support, Non-U.S. Gov't

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas FH et al. · Reproduction (Cambridge, England) · 2007 — PMID 17636166 ↗

Research Support, Non-U.S. Gov't

Enhanced response of granulosa and theca cells from sheep carriers of the FecB mutation in vitro to gonadotropins and bone morphogenic protein-2, -4, and -6

Campbell BK et al. · Endocrinology · 2006 — PMID 16396991 ↗

Research Support, N.I.H., Extramural

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Haluska P et al. · Cancer research · 2006 — PMID 16397250 ↗

Research Support, Non-U.S. Gov't

Potentiation of growth factor signaling by insulin-like growth factor-binding protein-3 in breast epithelial cells requires sphingosine kinase activity

Martin JL et al. · The Journal of biological chemistry · 2009 — PMID 19633297 ↗

Study

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 MG et al. · Journal of Alzheimer's disease : JAD · 2025 — PMID 39610283 ↗

Randomized Controlled Trial

Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells

Khamsi F et al. · Fertility and sterility · 2001 — PMID 11334915 ↗

Research Support, Non-U.S. Gov't

The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation

Pesall JE et al. · Poultry science · 2001 — PMID 11469659 ↗

Search this category on PubMed →

Animal 32

Study

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep

White A et al. · American journal of physiology. Endocrinology and metabolism · 2025 — PMID 39679943 ↗

Research Support, N.I.H., Extramural

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

White A et al. · Journal of developmental origins of health and disease · 2023 — PMID 37114757 ↗

Study

Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration

Yavuz E et al. · International journal of biological macromolecules · 2025 — PMID 41015370 ↗

Research Support, N.I.H., Extramural

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

Jonker SS et al. · FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2020 — PMID 32573852 ↗

Research Support, N.I.H., Extramural

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

Stremming J et al. · American journal of physiology. Endocrinology and metabolism · 2021 — PMID 33427051 ↗

Research Support, Non-U.S. Gov't

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

Levolger S et al. · Scientific reports · 2019 — PMID 31285507 ↗

Research Support, Non-U.S. Gov't

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

Sundgren NC et al. · American journal of physiology. Regulatory, integrative and comparative physiology · 2003 — PMID 12947030 ↗

In Vitro 20

Research Support, N.I.H., Extramural

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

White A et al. · Journal of developmental origins of health and disease · 2023 — PMID 37114757 ↗

Study

Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep

Stremming J et al. · Frontiers in physiology · 2022 — PMID 36091374 ↗

Research Support, Non-U.S. Gov't

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

Levolger S et al. · Scientific reports · 2019 — PMID 31285507 ↗

Research Support, N.I.H., Extramural

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Haluska P et al. · Cancer research · 2006 — PMID 16397250 ↗

Research Support, Non-U.S. Gov't

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

Sundgren NC et al. · American journal of physiology. Regulatory, integrative and comparative physiology · 2003 — PMID 12947030 ↗

Research Support, N.I.H., Extramural

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

White A et al. · American journal of physiology. Endocrinology and metabolism · 2021 — PMID 33938236 ↗

Research Support, Non-U.S. Gov't

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas FH et al. · Reproduction (Cambridge, England) · 2007 — PMID 17636166 ↗

Studies are surfaced live from the U.S. National Library of Medicine (PubMed). biohackr indexes and links the published record; it does not host or alter source articles.

IGF-1 LR3

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

The role of IGFBP-3 in the regulation of IGFBP-4 proteolysis

Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Enhanced response of granulosa and theca cells from sheep carriers of the FecB mutation in vitro to gonadotropins and bone morphogenic protein-2, -4, and -6

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Potentiation of growth factor signaling by insulin-like growth factor-binding protein-3 in breast epithelial cells requires sphingosine kinase activity

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

Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells

The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration

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

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

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

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

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

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

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

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

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

The role of IGFBP-3 in the regulation of IGFBP-4 proteolysis

Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Enhanced response of granulosa and theca cells from sheep carriers of the FecB mutation in vitro to gonadotropins and bone morphogenic protein-2, -4, and -6

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

Potentiation of growth factor signaling by insulin-like growth factor-binding protein-3 in breast epithelial cells requires sphingosine kinase activity

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

Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells

The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration

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

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

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

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

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets

Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting

In vitro and in vivo antitumor effects of the dual insulin-like growth factor-I/insulin receptor inhibitor, BMS-554417

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

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

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

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

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

The role of insulin-like growth factors in small intestinal cell growth and development

Insulin-like growth factor I (IGF-I) and long R(3)IGF-I differently affect development and messenger ribonucleic acid abundance for IGF-binding proteins and type I IGF receptors in in vitro produced bovine embryos

The local expression and abundance of insulin-like growth factor (IGF) binding proteins in skeletal muscle are regulated by age and gender but not local IGF-I in vivo

Na+ transport across rumen epithelium of hay-fed sheep is acutely stimulated by the peptide IGF-1 in vitro

Insulin-like growth factor I (IGF-I) and long R(3)IGF-I differently affect development and messenger ribonucleic acid abundance for IGF-binding proteins and type I IGF receptors in in vitro produced bovine embryos

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

Interaction of bovine granulosa and theca cells in a novel serum-free co-culture system

Enhanced response of granulosa and theca cells from sheep carriers of the FecB mutation in vitro to gonadotropins and bone morphogenic protein-2, -4, and -6