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Long-Arg3 IGF-1 (long-acting IGF-1 analog)
Supply and ordering
Ask sales about IGF-1 LR3 availability, order quantities, packaging, and batch documentation. Include other catalog items in the same inquiry if you are planning a combined or recurring order.
Overview
IGF-1 LR3 (Long R3 IGF-1) is an engineered 83-amino-acid analog of native IGF-1 with two structural modifications: a 13-amino-acid N-terminal extension and an Arg substitution at position 3 (in place of native Glu3). The N-terminal extension came originally from a serendipitous E. coli fusion-protein construct and was found to dramatically reduce binding affinity for the IGF-binding-protein family (IGFBPs), while the Arg3 substitution further suppresses IGFBP interaction. Both modifications together produce a circulating analog that is largely free of IGFBP sequestration, the practical consequence is roughly 3-fold higher biological potency in cell-proliferation assays compared with native IGF-1 at equivalent molar concentrations, plus an extended functional half-life because the molecule is not removed from circulation by IGFBP-mediated clearance. PeptideXpo supplies recombinant IGF-1 LR3 as a lyophilized powder to a ≥99.0% HPLC purity specification. As a recombinant protein expressed in E. coli, every released lot comes with its batch COA reporting RP-HPLC chemical purity and MS identity; SDS-PAGE size confirmation and a cell-proliferation bioassay (3T3 or MCF-7 cells) for activity confirmation are available on request and listed on the COA when tested. Endotoxin (LAL) is included by default for IGF-1 LR3 because the recombinant-protein process can carry over higher endotoxin loads than synthetic peptides. Two standard fill sizes (0.1 mg, 1 mg) cover cell-culture aliquot scales through in vivo research workflows.
Who buys this, and why
GH-axis peptides ship to two main buyer types: compounding pharmacies dispensing under physician supervision, and research labs studying somatotropic-axis pharmacology. Pharmacies typically want sterile-filled vials with the full release packet (sterility, endotoxin, CCI); labs typically want bulk lyophilized powder with sequence verification. Blends (the CJC-1295 / Ipamorelin combination is the canonical example) are usually co-lyophilized rather than solution-mixed for potency stability.
Primary buyer fit: academic and contract research laboratories.
Specifications
Also available as a nasal spray (US stock)
Besides lyophilized vials, IGF-1 LR3 is stocked in the US as a ready-to-use nasal spray.
Documentation available on request
Each picture is a low-resolution preview of a report's first page, with batch and report numbers covered. For the full, clear report, ask our sales team, naming the product and strength.
Batch COAIGF-1 LR3 1 mg
HPLC purity · MS identity
Batch COA
Full, clear copy from sales
Independent test fails? Full refund. How it works
Regulatory note
Sold as a bulk active for research and for compounding-pharmacy formulation where local regulations permit (notably 503A / 503B in the United States and analogous regimes elsewhere). Not a finished dosage form. Sterile-filled vials are available with full release documentation; the buyer is responsible for verifying scheduling and dispense requirements in the destination market.
Selected literature
Frequently asked questions
Native IGF-1 is heavily sequestered by IGFBPs in serum and cell-culture environments, typically less than 1% of total IGF-1 is free at any given time. This makes dose-response work and concentration-controlled experiments difficult because the effective free concentration is hard to predict. IGF-1 LR3's two engineered modifications (N-terminal extension and Arg3 substitution) dramatically reduce IGFBP binding, producing a more linear and predictable dose-response. The practical readout in cell-proliferation assays is roughly 3-fold higher potency than native IGF-1 at equivalent molar concentrations, with substantially less inter-experiment variability.
At 83 amino acids, IGF-1 LR3 is at the boundary between large peptide and small protein, practically, it's produced by recombinant expression in E. coli rather than solid-phase synthesis. The analytical approach therefore differs from typical synthetic peptides: the batch COA reports RP-HPLC chemical purity and mass spec identity (sometimes intact-mass or peptide-mapping), while SDS-PAGE size confirmation and a bioactivity readout (cell-proliferation assay) are recommended and available on request, because recombinant material's biological activity can vary with folding even when chemical purity is high. Endotoxin (LAL) is essential for IGF-1 LR3 because the E. coli expression system requires careful endotoxin clearance during purification; it is available on request and listed on the COA when tested.
Lyophilized IGF-1 LR3 reconstitutes in 0.6% acetic acid (rather than plain water), the slight acidification keeps the protein in monomer form and avoids aggregation that can occur at neutral pH on dilute reconstitution. After reconstitution, dilute working stocks should be prepared in cell-culture-grade BSA-containing buffer (typically 0.1% BSA) to prevent adsorption to glass and plastic surfaces at low working concentrations, this is critical for cell-culture work at sub-100 ng/mL. Working stocks should be aliquoted into single-use volumes and held at -20 °C; lyophilized product follows the standard 24-month re-test window.
Yes. IGF-1 LR3 is also stocked as a ready-to-use nasal spray (0.1 mg, 1 mg) in 10 mL or 20 mL bottles, from 10 bottles of each. These orders ship from our US stock; ask our sales team for details and a quote.
Send any vial from your order to an independent laboratory of your choice. If the report shows the product does not meet the specification on its COA — purity below the stated minimum, or an identity that does not match — share the report with our sales team and we refund that product in full.
