Description
IGF-1 LR3 (Long R3 IGF-I) is an engineered 83-residue analogue of insulin-like growth factor 1, designed in Australia in the early 1990s to escape the binding proteins that neutralize native IGF-1. It is a standard growth-factor supplement in cell-culture and bioprocessing labs. Pure Peptides Canada supplies it as a lyophilized research reagent in 1 mg vials, with an independent Janoshik HPLC and mass-spectrometry report, CAD pricing and tracked shipping from inside Canada.
IGF-1 LR3 at a glance
- What it is: human IGF-1 (70 residues) with glutamic acid 3 replaced by arginine and a 13-residue extension added to the N-terminus, 83 amino acids in total.
- Why it was made: those two changes cut its binding to IGF-binding proteins, so far more of it stays free to act on the IGF-1 receptor in serum-containing systems.
- Where it is used: IGF-1 receptor signalling studies and as an insulin or IGF replacement in mammalian cell-culture media.
- Supplied as: sealed lyophilized powder, 1 mg, single vial or box of 10.
- Delivery: ships from inside Canada by tracked Xpresspost in 3–7 days ($25 CAD), or free in 4–12 days on orders over $299.
IGF-1 LR3
Long R3 IGF-I · LR3-IGF-1 · [Arg3]IGF-I with N-terminal extension
- Length
- 83 amino acids (13-residue extension + 70-residue IGF-1 with Arg3)
- Molecular weight
- ≈ 9.1 kDa
- Structure
- Three internal disulfide bonds, as in native IGF-1
- Target
- IGF-1 receptor (IGF-1R)
- Key property
- Greatly reduced affinity for IGF-binding proteins
- Form
- Lyophilized powder, sealed vial
- Sizes
- 1 mg (single or box of 10)
- SKU
- PP-IGF1LR3
Where the evidence stands
- Cell studies
- Animal models
- Controlled human trials
- Approved medicine
IGF-1 LR3 is a laboratory and bioprocessing reagent. It has not been developed as a human medicine.
What is IGF-1 LR3?
Insulin-like growth factor 1 drives cell growth and survival through the IGF-1 receptor, but in blood and serum most of it is locked up by six IGF-binding proteins. Researchers at Adelaide, the group behind the company GroPep, set out to make a version that would slip past them. Swapping glutamic acid at position 3 for arginine (the R3) and adding a 13-amino-acid extension at the front (the Long) did exactly that. The result, described in 1992, was many times more potent than native IGF-1 in cells grown with serum.
That property made Long R3 IGF-I a workhorse of bioprocessing, where it replaces insulin or native IGF-1 in media for Chinese hamster ovary and other production cell lines. In research labs it is used to study IGF-1 receptor signalling through the PI3K–Akt and MAPK pathways without the confounding effect of binding proteins.
Handling note: unlike the short peptides in most of our catalogue, IGF-1 LR3 is a folded small protein with three disulfide bonds. Gentle handling and low-adsorption plastics help preserve activity in solution. Regulatory status: IGF-1 and its analogues are not authorized for human use as research products in Canada and are on the World Anti-Doping Agency prohibited list. We sell IGF-1 LR3 strictly as a laboratory reagent.
What IGF-1 LR3 research looks at
- IGF-1 receptor signalling: PI3K–Akt, mTOR and MAPK activation in cultured cells.
- Cell-culture media: serum-free and low-serum formulations for production cell lines.
- Binding-protein biology: how IGFBPs regulate IGF availability, using LR3 as a non-binding comparator.
- Muscle and cell proliferation models: myoblast and fibroblast growth in vitro.
- Axis comparisons: alongside upstream GHRH and ghrelin-receptor peptides in the Growth & Signaling range.
Why researchers order IGF-1 LR3 from Pure Peptides Canada
Add a 1 mg vial or a box of 10 above. Orders over $299 ship free across Canada.
See lab resultsChecking an IGF-1 LR3 identity report
Use these numbers when you open the mass-spectrometry result for an IGF-1 LR3 peptide batch. The analogue has 83 residues, a 13-residue N-terminal extension followed by human IGF-I with arginine at position 3, and three disulfide bonds. Its formula is C400H619N111O115S9.
- Electrospray charge states (average m/z): [M+7H]7+ 1302.6, [M+8H]8+ 1139.9, [M+9H]9+ 1013.4 and [M+10H]10+ 912.2.
- Deconvoluted mass: near 9111.5 Da (average). The monoisotopic mass is 9105.35 Da.
- Disulfide check: the fully reduced chain is 6.05 Da heavier, about 9117.5 Da (average). A deconvoluted mass near that figure suggests the disulfide bonds are not intact.
- MALDI: the singly charged ion, [M+H]+, appears at about m/z 9112.5 (average).
Our peptide mass-spectrum guide explains how software turns a charge-state ladder into a single deconvoluted mass. For the reports themselves, see the Lab Testing page, where Janoshik results are listed by product and batch.
IGF-1 LR3 FAQ
Where can I buy IGF-1 LR3 in Canada?
Pure Peptides Canada stocks IGF-1 LR3 as a lyophilized research reagent in 1 mg vials and ships it from inside Canada by tracked Xpresspost in 3–7 days ($25 CAD), or free in 4–12 days on orders over $299.
What is the difference between IGF-1 LR3 and native IGF-1?
IGF-1 LR3 has an arginine at position 3 and a 13-residue N-terminal extension. Those changes sharply reduce binding to IGF-binding proteins, so it stays active much longer in serum-containing systems.
What does LR3 stand for?
Long R3: Long for the 13-amino-acid N-terminal extension, R3 for the arginine substituted at position 3.
Is this IGF-1 LR3 third-party tested?
Yes. An HPLC purity and mass-spectrometry identity report from Janoshik Analytical, an independent lab, is listed on our Lab Testing page. For a protein this size, the mass confirms the full-length analogue. Our COA guide explains how to read the report.
Can IGF-1 LR3 be used in people or animals?
No. This product is for in-vitro laboratory research only and is not a drug, supplement or food. We do not provide dosing or administration information.
For laboratory research use only. Not a drug, supplement, food or cosmetic, not for human or veterinary use, and not intended to diagnose, treat, cure or prevent any disease.
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