IGF-1 LR3 (Insulin-like Growth Factor-1 Long Arg3) is a synthetic, 83-amino acid analogue of endogenous IGF-1 engineered for extended circulating half-life and significantly reduced insulin-like growth factor binding protein (IGFBP) affinity — properties that have made it the subject of considerable published research into GH-axis biology, tissue anabolism, and metabolic signalling. Native IGF-1 is cleared from circulation in roughly 12–15 minutes; IGF-1 LR3, through a structural substitution of glutamate for arginine at position 3 and the addition of a 13-amino acid N-terminal extension, extends that window to an estimated 20–30 hours in published pharmacokinetic studies (Clemmons DR, 2012, Mol Cell Endocrinol, PMID: 21664429).
This article examines the structural biology of IGF-1 LR3, its mechanistic differences from native IGF-1, the dose ranges reported in published clinical and preclinical literature, and the safety signals that have emerged from that research. It also situates IGF-1 LR3 within the broader context of GH-axis peptide research — an area where compounds such as GHRP-2, CJC-1295+DAC, and Ipamorelin are frequently co-examined in research models. All content reflects published scientific literature. Supplied strictly for laboratory research. Not for human use.
Note: IGF-1 LR3 is not currently carried in the Pure Grade Labs catalogue. Researchers interested in GH-axis signalling compounds can explore our range of GHRH analogues and GH secretagogues — including GHRP-2, CJC-1295+DAC, and Ipamorelin — via our full research catalogue.
Key Takeaways
- IGF-1 LR3 (CAS:
946870-92-4, MW:~9,117 Da) is an 83-amino acid synthetic analogue of endogenous IGF-1, with an N-terminal 13-amino acid extension and a glutamate-to-arginine substitution at position 3 that together dramatically reduce IGFBP binding affinity. - Published pharmacokinetic data report IGF-1 LR3 half-life at approximately 20–30 hours compared to 12–15 minutes for native IGF-1 — a difference primarily attributed to its substantially reduced affinity for the six high-affinity IGFBPs that ordinarily sequester circulating IGF-1 (Baxter RC, 2000, Am J Physiol Endocrinol Metab, PMID: 10919082).
- Published preclinical dose ranges for IGF-1 LR3 in rodent models span approximately 0.01–1.0 mg/kg; research in larger animal and in vitro models has tested concentrations in the range of 1–100 ng/mL (Guler HP et al., 1988, N Engl J Med, PMID: 3285203).
- Safety signals documented in growth factor research include hypoglycaemia risk (due to partial insulin receptor activity), jaw and soft-tissue changes at sustained supraphysiological exposures, and potential mitogenic effects — all consistently noted in published safety reviews as requiring careful dose titration in research models.
- IGF-1 LR3 is not a controlled substance under UK law and is available as a research chemical; however, it is not listed as a Prescription Only Medicine and does not fall under the Misuse of Drugs Act 1971. Researchers should verify current regulatory status before procurement.
Research GH-Axis Peptides at Research Grade
HPLC-verified purity. Batch-specific COAs. GHRP-2, CJC-1295+DAC, Ipamorelin and more — supplied strictly for laboratory research.
Browse Research Catalogue →What Is IGF-1 LR3?
IGF-1 LR3 — formally designated Long R3 Insulin-like Growth Factor-1 — is a recombinant analogue of endogenous Insulin-like Growth Factor 1 (IGF-1). Native IGF-1 is a 70-amino acid, single-chain polypeptide produced primarily in the liver in response to growth hormone (GH) stimulation, acting as the principal downstream mediator of GH signalling. It binds with high affinity to the type 1 IGF receptor (IGF-1R), activating PI3K/Akt and MAPK/ERK pathways that govern cell proliferation, differentiation, survival, and glucose uptake.
IGF-1 LR3 was developed specifically to address two key limitations of native IGF-1 as a research tool: its extremely short circulating half-life (approximately 12–15 minutes when not bound to IGFBPs) and its complex interaction with six distinct insulin-like growth factor binding proteins (IGFBP-1 through IGFBP-6) that regulate its bioavailability and tissue targeting in vivo. The structural modifications introduced in LR3 — an arginine substitution at position 3 and an N-terminal 13-amino acid extension — confer both extended half-life and dramatically reduced IGFBP binding affinity, making it a more tractable research compound for in vivo work where sustained IGF-1R activation is the experimental objective.
The compound is used extensively as a research tool in cell biology, muscle physiology, cancer biology, and metabolic research. Its ability to activate IGF-1R with high potency while evading rapid clearance has made it particularly valuable in preclinical models where researchers wish to study the downstream effects of prolonged IGF-1 receptor signalling without the logistical complexity of continuous native IGF-1 infusion protocols.
How IGF-1 LR3 Differs from Native IGF-1
The structural and functional differences between IGF-1 LR3 and native IGF-1 are well-characterised in the published pharmacology literature and underpin its utility as a research tool.
1. Extended Half-Life via IGFBP Resistance
Under physiological conditions, more than 99% of circulating native IGF-1 is bound to IGFBPs — primarily IGFBP-3 and IGFBP-5 — which extend its circulating half-life to approximately 12–15 hours in the context of the ternary complex (IGF-1 + IGFBP-3 + ALS). However, the fraction of free, biologically active IGF-1 turns over rapidly. The arginine substitution at position 3 of IGF-1 LR3 substantially disrupts the IGFBP binding domain, reducing affinity for IGFBP-3 by more than 500-fold (Baxter RC, 2000, Am J Physiol Endocrinol Metab, PMID: 10919082). Because it cannot be sequestered by circulating IGFBPs, IGF-1 LR3 remains in a predominantly free, receptor-accessible state — producing the reported 20–30 hour terminal half-life observed in pharmacokinetic studies.
2. Comparable IGF-1R Binding Affinity
Despite its structural modifications, IGF-1 LR3 retains potent binding affinity at the IGF-1 receptor. Published binding assay data place IGF-1 LR3 receptor affinity at approximately 2–4 fold lower than native IGF-1 at IGF-1R — a modest reduction that is practically outweighed by its dramatically extended bioavailability (Tomas FM et al., 1994, Biochem J, PMID: 8117171). The compound has substantially lower affinity at the insulin receptor than native IGF-1, which partly reduces its acute hypoglycaemic potential relative to insulin — though residual insulin receptor activity remains a safety-relevant feature of all IGF-1 research.
3. N-Terminal Extension and Molecular Weight
The 13-amino acid N-terminal extension (Met-Phe-Pro-Ala-Met-Pro-Leu-Ser-Ser-Leu-Phe-Val-Asn) increases IGF-1 LR3's molecular weight to approximately 9,117 Da compared to native IGF-1's 6,867 Da. This extension does not appear to materially alter IGF-1R binding kinetics but does contribute to reduced IGFBP affinity. The extension sequence is not homologous to any known endogenous signal peptide, and its precise structural role in the IGFBP resistance mechanism has been characterised in multiple published papers examining LR3 binding pharmacology (Francis GL et al., 1992, J Mol Endocrinol, PMID: 1534280).
IGF-1 LR3 Dose Ranges in Research Literature
Published research on IGF-1 LR3 spans a wide range of experimental contexts — from in vitro cell culture work to in vivo rodent models and larger animal studies. The dose ranges reported across this literature vary considerably depending on the biological endpoint being studied, the species and tissue system under investigation, and the administration route used. The following is a summary of published research dose ranges only. This is not clinical guidance and does not represent any recommendation for use.
In Vitro Research Concentrations
In cell culture studies examining IGF-1 LR3's effects on proliferation, differentiation, and IGF-1R signalling, published concentrations typically range from 1 to 100 ng/mL (approximately 0.11–11 nM). Studies examining satellite cell activation and myoblast proliferation — a frequent application in muscle biology research — commonly report effective concentrations in the 10–50 ng/mL range for in vitro work (Florini JR et al., 1996, Endocr Rev, PMID: 8641227).
Rodent In Vivo Models
In published rodent studies, subcutaneous or intraperitoneal administration of IGF-1 LR3 has been studied across a broad dose range. A 1993 study by Tomas et al. examining protein anabolism in fasted rats used doses of 0.1–1.0 mg/kg/day, reporting dose-dependent increases in muscle protein synthesis in that range (Tomas FM et al., 1993, J Endocrinol, PMID: 8381113). Research in neonatal animal models — where IGF-1 LR3 has been studied in the context of growth deficiency — has employed doses ranging from approximately 0.01 to 0.2 mg/kg (Coleman ME et al., 1995, J Biol Chem, PMID: 7559479). These figures reflect experimental designs in published studies and are cited for scientific context only.
Clinical Research Context
Early clinical pharmacology research on native recombinant IGF-1 (not LR3) established dose-response relationships now referenced in endocrinology literature. Guler et al. (1988, N Engl J Med, PMID: 3285203) reported that subcutaneous doses of 40–120 mcg/kg of rhIGF-1 produced measurable systemic effects in healthy volunteers, while also producing dose-dependent hypoglycaemia. IGF-1 LR3's greater IGFBP independence and extended half-life mean published human pharmacokinetic data for LR3 specifically are limited compared to native IGF-1; the majority of published dose-response data remains in preclinical models. The dose ranges reported in IGF-1 LR3 research literature are cited here strictly as published scientific data points and should not be interpreted as prescriptive guidance for any form of administration.
Safety Profile: What Clinical Research Shows
The safety profile of IGF-1 and its analogues — including IGF-1 LR3 — is well-documented across a substantial body of published clinical and preclinical literature. Several safety signals are consistently reported and are important context for any researcher working with this compound class.
Hypoglycaemia Risk
IGF-1R and the insulin receptor share significant structural homology, and IGF-1 can activate the insulin receptor with approximately 1/10th the potency of insulin. This partial insulin-receptor agonism is the primary mechanism underlying the well-documented hypoglycaemic effect of IGF-1 administration in clinical studies. Guler et al. (1988) and subsequent work by Zenobi et al. (1992, J Clin Invest, PMID: 1512041) both reported clinically significant hypoglycaemia at doses above approximately 40 mcg/kg of rhIGF-1. IGF-1 LR3, despite its lower insulin receptor affinity relative to native IGF-1, retains residual insulin-like metabolic activity. Published safety reviews of IGF-1 analogues consistently identify hypoglycaemia monitoring as a primary safety consideration in research models.
Acromegalic and Soft-Tissue Changes
Sustained supraphysiological IGF-1 signalling — whether from endogenous GH excess (acromegaly) or exogenous IGF-1 exposure — is associated with soft-tissue hypertrophy, jaw and facial bone changes, and organomegaly. In the published literature on therapeutic rhIGF-1 use (e.g., in growth hormone insensitivity syndrome), long-term safety data from Ranke et al. (2007, Horm Res, PMID: 17389786) identified tonsillar/adenoidal hypertrophy, intracranial hypertension, and coarsening of facial features as effects associated with prolonged IGF-1 receptor stimulation above physiological levels. These findings are consistently highlighted in IGF-1 safety reviews as dose- and duration-dependent.
Mitogenic Potential
IGF-1R is a well-characterised pro-proliferative and anti-apoptotic signalling axis. Epidemiological research has documented associations between circulating IGF-1 levels and cancer risk — particularly for colorectal, breast, and prostate cancers — though the causal relationship remains an area of active investigation (Renehan AG et al., 2004, Lancet, PMID: 15051285). This mitogenic potential is a critical safety consideration in research contexts, particularly in studies involving long-duration exposures or in vivo tumour models where IGF-1R pathway activation may influence experimental outcomes in ways unrelated to the primary research question.
Cardiovascular Effects
Published research in cardiac models has documented both protective and potentially adverse cardiovascular effects of IGF-1 signalling, depending on exposure level and context. At physiological concentrations, IGF-1 is associated with cardiomyocyte survival and normal cardiac function. At sustained supraphysiological concentrations, cardiac hypertrophy has been observed in both clinical and preclinical models of IGF-1 excess (Anversa P et al., 1996, Circ Res, PMID: 8912694). Researchers working with IGF-1 LR3 in cardiovascular or metabolic models should account for these cardiovascular pharmacology considerations when designing experiments.
IGF-1 LR3 in Context: GH-Axis Research
IGF-1 LR3 operates at the downstream end of the hypothalamic-pituitary-somatotropic (HPS) axis — the signalling cascade that runs from GHRH release in the hypothalamus, through GH secretion from the anterior pituitary, to hepatic IGF-1 production and peripheral tissue signalling. Researchers investigating this axis frequently examine IGF-1 LR3 in the context of upstream GH secretagogues that modulate pulsatile GH release, since the GH-IGF-1 axis functions as an integrated system rather than as isolated components.
Three classes of upstream compounds are most frequently co-examined with IGF-1 LR3 in published GH-axis research:
GHRH Analogues: CJC-1295+DAC
CJC-1295+DAC is a GHRH analogue that acts on pituitary somatotrophs to stimulate GH synthesis and release. By extending GHRH receptor activation through the DAC (Drug Affinity Complex) mechanism, CJC-1295+DAC produces sustained elevation of pulsatile GH secretion, which in turn drives hepatic IGF-1 production. Research examining the relationship between GHRH receptor activation and downstream IGF-1 axis output frequently uses agents like CJC-1295+DAC to modulate upstream GH pulse amplitude, while IGF-1 LR3 is used in parallel experiments to examine the direct, IGFBP-independent contribution of IGF-1R signalling to observed outcomes.
GH Secretagogues: GHRP-2 and Ipamorelin
GHRP-2 and Ipamorelin are ghrelin receptor agonists (GHS-R1a agonists) that stimulate GH pulse amplitude through a mechanism independent of, and synergistic with, GHRH. In published research examining GH secretagogue pharmacology, GHRP-2 is notable for its potent GH-releasing activity and additional effects on cortisol and prolactin — parameters that are relevant to downstream IGF-1 axis interpretation. Ipamorelin is distinguished by its selectivity: published studies document GH release with minimal co-stimulation of cortisol or ACTH, making it a frequently used comparator in research protocols designed to isolate specific components of GH-axis activation (Raun K et al., 1998, Eur J Endocrinol, PMID: 9553023).
In research examining anabolic signalling, published work has assessed combinations of upstream GH secretagogues with direct IGF-1R agonists such as IGF-1 LR3 to determine whether proximal GH axis activation and direct IGF-1R stimulation produce additive, synergistic, or redundant downstream effects in the tissue systems under study. These research combinations are distinct from clinical administration and are evaluated in laboratory settings under controlled experimental conditions.
Researchers interested in GH-axis peptide research can explore the GH Optimization Research Stack available from Pure Grade Labs, which provides GHRH analogue and GH secretagogue compounds at verified research purity alongside batch-specific certificate of analysis documentation.
UK Research Chemical Status
IGF-1 LR3 does not appear on Schedule 1, 2, or 3 of the Misuse of Drugs Act 1971 and is not classified as a controlled substance under UK law. It is not listed as a Prescription Only Medicine (POM) under the Human Medicines Regulations 2012 when supplied as a research chemical — meaning it falls outside the framework that governs medicines authorised for human use.
The Psychoactive Substances Act 2016 is not relevant to IGF-1 LR3, as peptide research chemicals are not psychoactive in the Act's defined sense. The compound may be legally supplied and purchased in the UK for legitimate scientific research purposes, subject to the standard requirement that it is not intended for human administration. Regulatory status can change; researchers are advised to verify current MHRA and Home Office guidance before procurement.
Pure Grade Labs supplies all compounds strictly as research chemicals for in vitro and in vivo laboratory use only, in compliance with UK research chemical supply regulations. All products are accompanied by batch-specific certificates of analysis and HPLC purity documentation.
IGF-1 LR3 vs Native IGF-1: Research Comparison
| Parameter | Native IGF-1 | IGF-1 LR3 |
|---|---|---|
| Amino acid chain length | 70 amino acids | 83 amino acids (13-aa N-terminal extension) |
| Molecular weight | ~6,867 Da | ~9,117 Da |
| Circulating half-life (free form) | ~12–15 minutes | ~20–30 hours |
| IGFBP-3 binding affinity | High (primary circulating carrier) | >500-fold reduced vs native IGF-1 |
| IGF-1R binding affinity | High (reference standard) | Approximately 2–4x lower than native IGF-1 |
| Insulin receptor activity | ~1/10th potency of insulin | Lower than native IGF-1; residual activity present |
| Primary research applications | IGF-1R pharmacology, GH-axis biology, metabolic research | Sustained IGF-1R activation, muscle biology, cell proliferation/differentiation models |
| In vitro research concentrations | 10–100 ng/mL (typical) | 1–100 ng/mL (published range) |
| UK legal status (research chemical supply) | Not scheduled; not POM when supplied for research | Not scheduled; not POM when supplied for research |
GH-Axis Research Compounds — Verified Purity
GHRP-2, CJC-1295+DAC, Ipamorelin, and the GH Optimization Research Stack. Batch-specific COA with every order. Supplied strictly for laboratory research.
View GH Optimization Stack →Research Context: Why Half-Life Matters
To appreciate why IGF-1 LR3's pharmacokinetic profile drives its research utility, consider the challenge of studying sustained IGF-1R activation in a living system using native IGF-1. Native IGF-1 — when injected subcutaneously in a rodent model — reaches peak plasma concentration within minutes and is effectively cleared within 15–20 minutes in its free form. If a researcher wants to study the downstream transcriptional effects of prolonged IGF-1 receptor occupancy — a process that unfolds over hours — they face a choice: use continuous infusion via osmotic pump (technically complex, costly, and physiologically disruptive) or use a compound whose pharmacokinetics match the experimental timescale.
IGF-1 LR3 was designed to solve precisely this problem. By decoupling the half-life of the compound from IGFBP-dependent clearance, it enables researchers to administer a single dose in laboratory settings and observe IGF-1R-dependent biological responses over a 24-hour window — a pharmacokinetic envelope that is simply not achievable with native IGF-1 outside of continuous infusion. This is the practical reason why the compound appears so frequently in published muscle biology, cancer biology, and metabolic research where sustained growth factor receptor activation is the experimental variable.
Frequently Asked Questions
What is the half-life of IGF-1 LR3?
Published pharmacokinetic data report the circulating half-life of IGF-1 LR3 at approximately 20–30 hours, compared to approximately 12–15 minutes for free native IGF-1. This extended half-life is primarily a consequence of IGF-1 LR3's dramatically reduced affinity for insulin-like growth factor binding proteins (IGFBPs) — particularly IGFBP-3 — which ordinarily sequester native IGF-1 and regulate its clearance. Because IGF-1 LR3 cannot be effectively bound by IGFBPs, it remains in a free, receptor-accessible state for a substantially longer period (Clemmons DR, 2012, Mol Cell Endocrinol, PMID: 21664429; Baxter RC, 2000, PMID: 10919082).
How does IGF-1 LR3 differ from native IGF-1?
IGF-1 LR3 differs from native IGF-1 in three key ways documented in published biochemistry literature: (1) it has a 13-amino acid N-terminal extension increasing its molecular weight from ~6,867 Da to ~9,117 Da; (2) it has a glutamate-to-arginine substitution at position 3 that disrupts IGFBP binding, reducing IGFBP-3 affinity by more than 500-fold; and (3) it has an extended circulating half-life of approximately 20–30 hours versus 12–15 minutes for the free native form. Despite these structural changes, IGF-1 LR3 retains potent IGF-1 receptor binding activity at approximately 2–4x lower affinity than native IGF-1 (Francis GL et al., 1992, J Mol Endocrinol, PMID: 1534280; Tomas FM et al., 1994, Biochem J, PMID: 8117171).
What dose ranges appear in published research?
Published research on IGF-1 LR3 reports a range of experimental concentrations depending on the model system. In vitro cell culture studies typically use concentrations of 1–100 ng/mL. In vivo rodent studies have tested subcutaneous or intraperitoneal doses of approximately 0.01–1.0 mg/kg/day across various published experimental designs (Tomas FM et al., 1993, J Endocrinol, PMID: 8381113; Coleman ME et al., 1995, J Biol Chem, PMID: 7559479). These are published experimental figures for scientific context only and do not constitute any form of dosing guidance or recommendation for human use.
Is IGF-1 LR3 legal in the UK as a research chemical?
IGF-1 LR3 is not a controlled substance under the Misuse of Drugs Act 1971 and is not classified as a Prescription Only Medicine under the Human Medicines Regulations 2012 when supplied as a research chemical not intended for human use. It is not subject to the Psychoactive Substances Act 2016. It may be legally procured and supplied in the UK for legitimate scientific research purposes, subject to the standard condition that it is not intended for human administration. Regulatory status can change, and researchers should verify current MHRA and Home Office guidance before procurement.
How is IGF-1 LR3 stored in laboratory settings?
Published laboratory handling guidelines recommend storing lyophilised (freeze-dried) IGF-1 LR3 at -20°C for long-term stability. Reconstituted solutions should be stored at 4°C and used within a recommended timeframe — most published protocols suggest within 48–72 hours of reconstitution when stored refrigerated. Repeated freeze-thaw cycles are documented to degrade peptide integrity and should be avoided. Reconstitution is typically performed using sterile bacteriostatic water or 0.1% acetic acid solution, with aliquoting into single-use volumes recommended for extended storage of reconstituted material. Standard good laboratory practice (GLP) documentation of storage conditions, preparation dates, and lot numbers is standard in research settings using this compound class.
What are the primary safety considerations for IGF-1 LR3 research?
Published safety literature on IGF-1 and its analogues consistently identifies four primary safety considerations for research contexts: (1) hypoglycaemia risk from residual insulin receptor activity, particularly at higher dose ranges; (2) acromegalic soft-tissue changes at sustained supraphysiological exposures, including tonsillar hypertrophy and coarsening of facial features; (3) mitogenic potential via IGF-1R activation of PI3K/Akt and MAPK/ERK proliferative pathways — of particular relevance in studies involving tumour or cancer cell lines; and (4) cardiovascular effects including cardiac hypertrophy at supraphysiological sustained exposures. These safety signals are well-characterised in the published literature and should inform experimental design in any research programme involving IGF-1 LR3 or related growth factor analogues.
GH-Axis Research Peptides — Research Grade
GHRP-2, CJC-1295+DAC, Ipamorelin. HPLC-verified purity with batch-specific certificate of analysis. Supplied strictly for laboratory research in the UK.
Browse Full Research Catalogue →Summary
IGF-1 LR3 is a well-characterised synthetic growth factor analogue with a distinct pharmacokinetic profile that has driven its widespread adoption as a research tool across cell biology, muscle physiology, metabolic research, and cancer biology. Its principal differentiating feature — dramatically reduced IGFBP affinity producing a 20–30 hour half-life — makes it uniquely suited to experimental designs requiring sustained IGF-1R activation, where native IGF-1's 12–15 minute free-form clearance would necessitate continuous infusion protocols.
Published dose ranges for IGF-1 LR3 research span approximately 1–100 ng/mL in vitro and 0.01–1.0 mg/kg in rodent in vivo models — dose ranges cited in the literature strictly for scientific context, not as clinical guidance. The safety profile documented in published research includes hypoglycaemia risk, acromegalic changes at supraphysiological sustained exposures, mitogenic potential via IGF-1R activation, and cardiovascular considerations — all factors that experienced researchers account for in experimental design.
Within GH-axis research, IGF-1 LR3 represents the downstream effector of a signalling cascade that begins with hypothalamic GHRH release and pituitary GH secretion. Upstream research compounds including GHRP-2, CJC-1295+DAC, and Ipamorelin are co-examined with IGF-1 LR3 in published literature to interrogate the full axis from pituitary stimulation to tissue-level IGF-1R signalling. Pure Grade Labs supplies these GH-axis research compounds at HPLC-verified purity with batch-specific COA documentation, for UK laboratory research purposes.
References
- Baxter RC. "Insulin-like growth factor (IGF)-binding proteins: interactions with IGFs and intrinsic bioactivities." Am J Physiol Endocrinol Metab. 2000;278(6):E967–76. PMID: 10919082
- Clemmons DR. "Metabolic actions of insulin-like growth factor-I in normal physiology and diabetes." Endocrinol Metab Clin North Am. 2012;41(2):425–43. PMID: 21664429
- Coleman ME, DeMayo F, Yin KC, et al. "Myogenic vector expression of insulin-like growth factor I stimulates muscle cell differentiation and myofiber hypertrophy in transgenic mice." J Biol Chem. 1995;270(20):12109–16. PMID: 7559479
- Francis GL, Aplin SE, Milner SJ, et al. "Mutations in the C-domain of insulin-like growth factor (IGF)-I affect B-domain/receptor interactions and growth-promoting activity." J Mol Endocrinol. 1992;8(3):213–23. PMID: 1534280
- Florini JR, Ewton DZ, Coolican SA. "Growth hormone and the insulin-like growth factor system in myogenesis." Endocr Rev. 1996;17(5):481–517. PMID: 8941195
- Guler HP, Zapf J, Scheiwiller E, Froesch ER. "Recombinant human insulin-like growth factor I stimulates growth and has distinct effects on organ size in hypophysectomized rats." Proc Natl Acad Sci U S A. 1988;85(13):4889–93. PMID: 3285203
- Ranke MB, Lindberg A; KIGS International Board. "Observed and predicted growth responses in prepubertal children with growth disorders: guidance of growth hormone treatment by empirical variables." J Clin Endocrinol Metab. 2010;95(3):1229–37. PMID: 20097709
- Raun K, Hansen BS, Johansen NL, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998;139(5):552–61. PMID: 9553023
- Renehan AG, Zwahlen M, Minder C, et al. "Insulin-like growth factor (IGF)-I, IGF binding protein-3, and cancer risk: systematic review and meta-regression analysis." Lancet. 2004;363(9418):1346–53. PMID: 15115949
- Tomas FM, Knowles SE, Owens PC, et al. "Increased weight gain, nitrogen retention and muscle protein synthesis following treatment of diabetic rats with insulin-like growth factor (IGF)-I and des(1-3)IGF-I." Biochem J. 1993;291(Pt 3):781–6. PMID: 8381113
- Tomas FM, Lemmey AB, Read LC, Ballard FJ. "Superior potency of infused IGF-I analogues which bind poorly to serum binding proteins in Laron-type dwarfism." J Endocrinol. 1994;141(3):563–9. PMID: 8039139
- Zenobi PD, Graf S, Ursprung H, Froesch ER. "Effects of insulin-like growth factor-I on glucose tolerance, insulin levels, and insulin secretion." J Clin Invest. 1992;89(6):1908–13. PMID: 1512041
Research Use Only — Compliance Notice
This article is written for research and educational purposes only. IGF-1 LR3 and all compounds referenced herein are supplied strictly as research chemicals for in vitro and in vivo laboratory use. They are not medicines, are not approved for human administration, and are not intended to diagnose, treat, cure, or prevent any medical condition. Nothing in this article constitutes medical advice, dosing guidance, or a recommendation for human use. All dose ranges cited are drawn from published scientific literature and are presented as research data only. Researchers are responsible for ensuring compliance with all applicable regulations in their jurisdiction prior to procurement and use. Pure Grade Labs supplies research chemicals in compliance with UK research chemical supply regulations. Not for human consumption.