IGF-1 LR3

Technical data

CAS

946870-92-4

Molecular formula

C400H625N111O115S9

Molecular weight

9117.6 g/mol

Identity and composition

IGF-1 LR3 (Long R3 IGF-1, Long [Arg3]-IGF-I) is a long-acting recombinant analog of insulin-like growth factor type 1, offered by EXOMA exclusively for research (RUO). It belongs to the class of modified somatomedins: an 83-amino-acid polypeptide (CAS 946870-92-4) that differs from native IGF-1 in two key features. At position 3 it substitutes glutamate with arginine (Glu3→Arg), which drastically reduces its affinity for the binding proteins (IGFBP), and it adds a 13-amino-acid N-terminal extension that increases its stability and half-life. As an agonist of the IGF-1R receptor, it activates PI3K/Akt and MAPK signaling cascades linked to proliferation, differentiation and protein synthesis. It comes lyophilized in a 0.1 mg vial, ideal for controlled laboratory protocols. Those seeking to buy IGF-1 LR3 Mexico find in this molecule a reproducible tool for studying the GH/IGF-1 axis. All material is intended solely for research, with documentation of identity, purity and lot traceability.

Mechanism of action

The mechanism of IGF-1 LR3 centers on its high-affinity binding to the IGF-1R receptor, a transmembrane tyrosine kinase. Upon binding to the extracellular domain, it triggers autophosphorylation of tyrosine residues and recruitment of IRS-1/IRS-2 substrates, activating two main pathways: the PI3K/Akt pathway, associated with cell survival, glucose uptake and inhibition of apoptosis, and the MAPK/ERK pathway, linked to proliferation and growth. The distinctive feature of Long R3 IGF-1 is its very low affinity for the IGFBPs due to the Glu3→Arg substitution; by not being sequestered by these carrier proteins, a much larger fraction of the peptide remains free and bioavailable to interact with IGF-1R. This amplifies and prolongs signaling relative to native IGF-1. The 13-amino-acid N-terminal extension reinforces this evasion of the IGFBPs and contributes to resistance to degradation. In research models, this sustained activation of PI3K/Akt and MAPK translates into more pronounced responses on protein synthesis, reserved for research use (RUO).

Pharmacokinetics

The pharmacokinetic profile of IGF-1 LR3 is its defining advantage over the native peptide. Its half-life is estimated at 20-30 hours, far greater than the few minutes of conventional free IGF-1, and its potency is 2-3 times higher. This durability is explained by its low affinity for the IGFBPs: under normal physiological conditions, IGF-1 circulates almost entirely bound to these proteins, which regulate its release and clearance; by evading them thanks to the Glu3→Arg substitution and the 13-amino-acid N-terminal extension, Long R3 IGF-1 avoids that sequestration and the rapid clearance, maintaining active concentrations for much longer. The result is prolonged exposure of the IGF-1R receptor with lower molar doses. For experimental design, these kinetics allow administrations to be spaced out and sustained effects on the PI3K/Akt and MAPK pathways to be observed in in vitro and in vivo models. Researchers who look up the IGF-1 LR3 price tend to value precisely this efficiency per unit of mass. All use remains strictly for research (RUO).

Scientific evidence

Preclinical evidence places IGF-1 LR3 within the somatotropic GH/IGF-1 axis, in which growth hormone induces hepatic production of IGF-1, a mediator of many of its anabolic effects. In research models, IGF-1 analogs with low affinity for IGFBPs show an enhanced capacity to stimulate protein synthesis, amino acid uptake, and growth signaling through PI3K/Akt. Experimental studies on muscle tissue describe processes of both hypertrophy (increase in the size of existing fibers) and hyperplasia (proliferation of satellite cells and potential increase in the number of fibers), phenomena linked to sustained activation of IGF-1R. Its role in cell differentiation, tissue repair, and glucose metabolism in controlled systems is also documented. It should be emphasized that these findings come from laboratory contexts and do not constitute clinical indications: Long R3 IGF-1 is studied for research use only (RUO), as a tool for characterizing mechanisms of the GH/IGF-1 axis.

Research applications

In the strictly experimental setting, IGF-1 LR3 is used as a tool to interrogate the biology of the IGF-1R receptor and the PI3K/Akt and MAPK pathways. Research groups use it in cell cultures to study proliferation, myogenic differentiation, survival and stress response, taking advantage of its prolonged signaling and its independence from the IGFBPs, which simplifies the interpretation of dose-response assays. In muscle and connective tissue models it serves to explore mechanisms of hypertrophy, hyperplasia and repair; in metabolic studies, to characterize glucose uptake and protein synthesis. Its stable kinetics make it useful as a reference agonist against other analogs such as IGF-1 DES or the native peptide. It is also applied in research on developmental biology and cellular aging. Those wishing to buy IGF-1 LR3 Mexico for these purposes find in EXOMA material characterized by lot. None of these applications imply use in humans: the molecule is offered only for research (RUO).

Research protocols

The laboratory handling protocols for IGF-1 LR3 start from the lyophilized 0.1 mg vial and prioritize reproducibility and sterility. After reconstitution in 0.6% acetic acid, it is common to prepare working aliquots to avoid repeated freeze-thaw cycles that degrade the peptide. In in vitro designs, dose-response curves usually span nanomolar ranges to characterize the activation of IGF-1R and PI3K/Akt signaling, adjusting concentrations according to the cell type. Given the 2-3 times greater potency and the 20-30 hour half-life of Long R3 IGF-1, the intervals between administrations in experimental models can be spaced out relative to native IGF-1. It is recommended to record batch, reconstitution date, and storage conditions for traceability. Handling demands good laboratory practices, control of the medium's pH, and verification of activity through appropriate assays. These guidelines are purely methodological and orientative: any work with the molecule is carried out solely for research (RUO), without extrapolation to clinical contexts.

Reconstitution

The reconstitution of IGF-1 LR3 is carried out with 0.6% acetic acid, using between 0.5 and 1 mL for the 0.1 mg vial depending on the desired working concentration. The liquid is added carefully down the wall of the vial, avoiding vigorous shaking that can denature the peptide; it is allowed to dissolve slowly until a clear solution is obtained. The reason for the acidic pH is physicochemical: Long R3 IGF-1 shows greater solubility and stability in a slightly acidic medium, where its folding and disulfide bonds are better preserved than in neutral or alkaline solutions, which favor aggregation and loss of activity. Dilute acetic acid protonates ionizable groups and keeps the peptide in solution without compromising its tertiary structure. For subsequent assays, the aliquot can be diluted in the buffer compatible with the experimental system. It is advisable to prepare only the necessary volume and to store aliquots. This procedure applies to material intended exclusively for research use (RUO); those evaluating IGF-1 LR3 price should also consider these handling supplies.

Stability and storage

The stability of IGF-1 LR3 depends on a well-managed cold chain. In its lyophilized form, the 0.1 mg vial is optimally preserved at -20 °C, a condition under which the peptide remains stable for prolonged periods when protected from moisture and light. Once reconstituted in 0.6% acetic acid, the solution should be kept refrigerated at 2-8 °C and used within a maximum of 14 days, since in a liquid medium the processes of hydrolysis, oxidation, and aggregation accelerate progressively. For longer-term storage of the reconstituted material, common laboratory practice is to aliquot and freeze, minimizing freeze-thaw cycles that fragment the chain and reduce activity on IGF-1R. It is advisable to label each aliquot with date and lot, to avoid repeated exposure to room temperature, and to protect from direct light. Careful handling preserves the 2-3 times greater potency and the characteristic half-life of Long R3 IGF-1. These conditions ensure reproducible results in work intended for research use only (RUO).

Safety profile

In the experimental handling of IGF-1 LR3, the pharmacological properties of the compound must be considered, even though its use is strictly for research (RUO). Because of its activation of the PI3K/Akt pathway, it shares mechanisms with insulin signaling and can, in biological systems, influence glucose uptake; for this reason, in in vivo models a hypoglycemic potential is documented that demands rigorous metabolic controls. The sustained activation of IGF-1R by an agonist with a half-life of 20-30 hours and 2-3 times greater potency requires a cautious experimental design in dose and frequency. In the laboratory, handling requires personal protective equipment, aseptic technique, and appropriate disposal of biological waste. Long R3 IGF-1 is not intended for diagnosis or for application in living beings outside authorized research protocols. EXOMA supplies the molecule with batch documentation to support safe and traceable practices. All of this information is guidance for the researcher and does not constitute clinical guidance of any kind, since the material is offered solely for research.

Comparative context

Understanding IGF-1 LR3 requires situating it against related molecules. Relative to native IGF-1, Long R3 IGF-1 provides a much longer half-life (20-30 hours versus minutes) and 2-3 times greater potency, owing to its low affinity for IGFBPs derived from the Glu3→Arg substitution and the 13-amino-acid N-terminal extension. Compared with IGF-1 DES, another truncated analog that also evades IGFBPs but has very short and local action, LR3 stands out for its systemic durability, which makes it preferable for studies requiring prolonged receptor exposure. Compared with HGH or somatropin, the difference is one of level within the GH/IGF-1 axis: growth hormone acts upstream by inducing endogenous IGF-1 production and exerts its own effects on lipolysis and metabolism, whereas IGF-1 LR3 acts downstream, as a direct IGF-1R agonist. These distinctions guide the choice of tool according to the experimental question. All of these analogs are offered for research use only (RUO); comparing IGF-1 LR3 price and profile helps in selecting the appropriate reagent.

History and development

The development of IGF-1 LR3 is set within decades of research on insulin-like growth factor 1, originally identified as somatomedin C, the mediator of many of the anabolic effects of growth hormone within the GH/IGF-1 axis. With the advance of recombinant DNA technology in the 1980s and 1990s, scientists designed analogs to overcome the practical limitation of native IGF-1: its fleeting half-life due to sequestration by IGFBPs. Thus arose Long [Arg3]-IGF-I, which combines two rational modifications, the Glu3→Arg substitution and a 13-amino-acid N-terminal extension, to reduce binding to those carrier proteins and prolong activity. Produced recombinantly, IGF-1 LR3 was widely adopted as a supplement in cell culture and as a reagent in growth biology, where its stability and potency made it a reference standard. Today, EXOMA offers it characterized per lot for research (RUO). Those seeking to buy IGF-1 LR3 Mexico gain access to an analog with a well-established scientific track record.

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Scientific references (6)

Peer-reviewed literature on IGF-1 LR3, with its PubMed identifier when available:

• Type I insulin-like growth factor receptor signaling in skeletal muscle regeneration and hypertrophy (Philippou A, et al. · Journal of Musculoskeletal and Neuronal Interactions · 2007) — Review of the role of IGF-1 in skeletal muscle regeneration. PMID 17947802.
• Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency (Francis, et al. · Journal of Molecular Endocrinology · 1992) PMID 1378742.
• Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection (Tomas, et al. · Journal of Endocrinology · 1996) PMID 8708565.
• IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep. (White A, et al. · Am J Physiol Endocrinol Metab · 2025) PMID 39679943.
• 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. · J Dev Orig Health Dis · 2023) PMID 37114757.
• Long [R3] insulin-like growth factor-I reduces growth, plasma growth hormone, IGF binding protein-3 and endogenous IGF-I concentrations in pigs. (Dunaiski V, et al. · J Endocrinol · 1997) PMID 9488001.

Guides and articles about IGF-1 LR3

Lecturas del blog de EXOMA que la editorial asoció a este compuesto:

• IGF-1 LR3: Insulin-like Growth Factor - Scientific Guide

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