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IGF-1 LR3
IGF-1 LR3, 83-amino acid extended IGF-1 analogue with Arg3 substitution eliminating IGFBP binding for 3-fold enhanced potency and 20–30 hour half-life.
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PRECISION. PURITY. PERFORMANCE.
Research peptides at >99% HPLC-verified purity, third-party tested by Janoshik Analytical & Freedom Diagnostics, with Certificates of Analysis published per released batch. Supplied strictly for laboratory research use.
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Research use only - all claims made on this site are for testing and research use only. Purchasers must be 21 years of age or older.
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IGF-1 LR3
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Lab-direct quality — full packs or single-vial samples
Every batch ships straight from the lab that synthesises it — sealed, tamper-evident, and HPLC-verified to >99% purity . Buying direct means you pay the lab-direct rate on every vial, with nothing stacked on top.
Order a sealed 10-vial research pack , or add a single-vial laboratory sample alongside your pack to evaluate a compound at smaller scale first. Same lab, same batch, same verified purity — scaled to whatever your research needs.
What It's Researched For
In plain terms, IGF-1 LR3 is studied mainly as a muscle-growth and cell-growth research compound. Here is what that looks like across the research.
Muscle growth & new muscle cells
Research explores how it switches on muscle stem cells and the formation of new muscle cells.
Protein building & repair
Studied for ramping up the protein-synthesis machinery that muscle and connective tissue use to rebuild.
Lab cell-growth standard
Widely used as a standard growth factor to keep cultured cells alive and multiplying in cell-culture and bioprocessing research.
Nutrient & glucose uptake
Research looks at how it helps cells take up glucose and amino acids, overlapping with insulin signalling.
Long-acting IGF-1 model
Used as a long-lasting version of natural IGF-1 to study its signalling without it being mopped up in the bloodstream.
Overview
In short: IGF-1 LR3 (Long Arginine 3 IGF-1) is an 83-amino-acid recombinant IGF-1 analog engineered to escape IGF-binding protein sequestration, giving it roughly 3× the potency and a 20-30 hour half-life of native IGF-1.
Key research facts
These points summarise lab themes, not human outcomes.
IGF-1 (insulin-like growth factor 1) is the hormone that does most of the downstream anabolic work when growth hormone is around. Problem: in the bloodstream, roughly 98% of native IGF-1 is bound up by a family of six IGF-binding proteins (IGFBPs) that act as a buffer, keeping the free, active fraction tiny.
IGF-1 LR3 is an engineered version designed to defeat that buffer. It has two modifications: a 13-amino-acid N-terminal extension (MFPAMPLSSLFVN) and a single amino acid substitution that replaces glutamate at position 3 with arginine. Together, those changes virtually eliminate IGFBP binding, leaving the peptide free and active in circulation.
The practical consequence is roughly 3x greater in-vivo potency than native IGF-1 and a dramatically extended half-life of 20-30 hours versus 12-15 hours. IGF-1 LR3 is widely used in cell culture, bioprocessing, and muscle/performance research. Supplied here as sterile lyophilised powder.
Mechanism of Action
IGF-1 LR3 activates the IGF-1 receptor directly - driving protein synthesis, cell proliferation, and glucose uptake - without getting trapped by circulating IGF-binding proteins.
Francis et al. (Journal of Molecular Endocrinology, 1992) characterised the LR3 analog and showed that the combined N-terminal extension and Arg3 substitution reduce IGFBP binding to less than 2% of native IGF-1, raising free bioavailability dramatically. Circulating half-life extends from 12-15 h (native IGF-1) to 20-30 h (LR3). Originally developed by CSIRO Australia and commercialised by Repligen under the LONG R3 IGF-I trademark for cell culture and bioprocessing applications. Banned by WADA for competing athletes.
Common Questions People Are Asking
What is IGF-1 LR3?
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is an 83-amino-acid analogue of human IGF-1 with an N-terminal extension and an Arg substitution at position 3. Those modifications stop it binding IGF-binding proteins, greatly extending its active half-life versus native IGF-1. It is supplied as a lyophilised research-grade powder for laboratory use only.
What does IGF-1 LR3 do?
In research models IGF-1 LR3 activates the IGF-1 receptor (and PI3K/Akt and MAPK signalling) to drive cell growth, proliferation, differentiation and survival - with a much longer duration of action than native IGF-1 because it evades IGFBP sequestration. These are findings in cell and animal models; New-U supplies it for laboratory research only and implies no human effect.
What is IGF-1 LR3 used for?
IGF-1 LR3 is widely used as a cell-culture supplement to support proliferation and survival of cultured cells, and as a research tool for studying IGF-1-receptor signalling, hypertrophy and tissue-growth endpoints. New-U supplies it strictly for in-vitro and laboratory research.
Does IGF-1 LR3 show up on a drug test?
Standard employment or clinical drug panels (including typical LabCorp steroid panels) do not screen for IGF-1 LR3 - it is a peptide, not a small-molecule steroid, and requires specialised assays. It is, however, on the WADA Prohibited List, and anti-doping authorities use dedicated tests for IGF-1 analogues.
What does "LR3" actually mean?
"L" for the 13-amino-acid N-terminal extension (MFPAMPLSSLFVN), "R" for arginine, and "3" for position 3 of the IGF-1 sequence. So "LR3" literally means "the Long variant with an Arginine at position 3". Both modifications are needed to eliminate IGFBP binding and extend circulating half-life.
How is IGF-1 LR3 different from IGF-1 DES?
IGF-1 DES is the opposite end of the design spectrum - a truncated 67-residue form missing the N-terminal tripeptide GPE, which also dramatically reduces IGFBP binding. IGF-1 LR3 uses a 13-residue extension to achieve similar IGFBP resistance. LR3 has a much longer half-life (20-30 h vs minutes); DES produces more intense, shorter-duration local effects when injected site-specifically.
Why is IGF-1 LR3 used in cell culture?
Native IGF-1 is inefficient in cell culture because IGFBPs produced by the cells themselves can sequester it, reducing effective concentrations. IGF-1 LR3 escapes that sequestration and delivers consistent, reproducible growth-factor signalling. That is why it is an industry standard for bioprocessing and mammalian cell culture.
How should IGF-1 LR3 be stored?
Keep the lyophilised powder frozen at −20 °C (−80 °C for long-term storage). After reconstitution, refrigerate at 1-6 °C and protect from light. IGF-1 LR3 is a structured protein and is sensitive to repeated freeze-thaw cycles - aliquot if you need multiple aliquots from one reconstitution.
How is IGF-1 LR3 reconstituted in the lab?
Because IGF-1 LR3 is a structured protein that tends to aggregate in neutral aqueous solution, laboratory practice commonly reconstitutes it in dilute acetic acid (around 0.1%, ~10 mM) rather than plain water, which keeps it in a non-aggregated state; bacteriostatic or sterile water is also used. The vial is allowed to reach room temperature before opening to avoid condensation, then gently rolled rather than shaken. This is general handling guidance for research material, not a dosing instruction.
Where can I buy IGF-1 LR3?
Right here - IGF-1 LR3 is supplied directly by New-U Research Compounds on this page. Every batch is independently third-party tested to >99% HPLC purity with a batch-linked Certificate of Analysis, supplied as lyophilised research-grade material, and shipped direct from source worldwide in discreet, tracked packaging.
How much does IGF-1 LR3 cost?
IGF-1 LR3 pricing is shown live on this page, per pack size - 10-vial research packs as standard, with single-vial sample options on selected compounds. Larger vial strengths lower the per-mg cost, every order includes the batch Certificate of Analysis, and shipping is free on orders over $350.
Is IGF-1 LR3 third-party tested?
Yes. Every IGF-1 LR3 batch is verified by independent laboratories (Janoshik Analytics and Freedom Diagnostics) for identity and purity, with a batch-linked Certificate of Analysis confirming >99% purity by HPLC. Every order ships with its COA, and current batch certificates are published on our COA page.
How do I buy IGF-1 LR3?
Add the IGF-1 LR3 pack size you need to your cart and check out: enter your shipping details, then choose your payment method - cryptocurrency or card - on the next step. Every order ships with its batch Certificate of Analysis (COA).
What payment methods can I use to buy IGF-1 LR3?
At checkout you can pay by card or crypto. New-U supports BTC and selected stablecoin and network-asset payments across Ethereum, Solana, TRON, Polygon, Base, BNB Chain and Linea. You choose your method after confirming your order.
How fast is shipping, and do you ship worldwide?
Yes - we ship worldwide in discreet, unmarked, temperature-stable, tracked packaging. Delivery typically takes 6–14 business days, and shipping is free on orders over $350.
Is it legal to buy IGF-1 LR3?
In the United States, IGF-1 LR3 is sold strictly for laboratory and research purposes only. It is not approved by the FDA for human consumption and is not sold for that purpose. Regulatory status varies by jurisdiction - buyers are responsible for compliance in their own region.
Research use only - all claims made on this site are for testing and research use only.
Pharmacokinetics
Evidence Tier
Overall: Tier 2: Animal / preclinical
IGF-1 LR3 has robust mammalian in-vivo characterisation (pigs, marmoset monkeys, DMD models) and is an industry-standard in-vitro cell-culture growth factor, but there are no human clinical trials of the LR3 analogue itself. The native molecule mecasermin (rhIGF-1) is FDA-approved for paediatric primary IGF-1 deficiency, whereas LR3 specifically is unapproved research-only material and is on the WADA Prohibited List.
Tier 2 · Animal
Certificates, databases & peer-reviewed sources
Last reviewed: 16 June 2026 · New-U Research Compounds
Key Characteristics
Specifications
About IGF-1 LR3 (Long R3 IGF-1): IGF-1 Signalling & Cell-Culture Research Guide
IGF-1 LR3 was originally engineered for the cell culture and bioprocessing industry rather than for medicine. The fundamental problem it solves is that native IGF-1 has a free-fraction problem: most of the peptide in circulation is sequestered by IGF-binding proteins (IGFBPs), so useful concentrations require high doses. Adding a 13-residue N-terminal extension (MFPAMPLSSLFVN) and swapping glutamate for arginine at position 3 breaks the IGFBP interaction and leaves the peptide free and active - the basis for its roughly 3-fold greater potency and its much longer 20-30 hour half-life versus native IGF-1.
Repligen commercialised the modified peptide under the LONG R3 IGF-I trademark, and it became an industry-standard growth factor for mammalian cell culture. Researchers studying muscle growth, satellite-cell activation, recovery, and connective-tissue repair then picked it up as a tool compound for studying IGF-1-receptor (PI3K/Akt/mTOR and RAS/RAF/MEK/ERK) pharmacology without the complication of the IGFBP buffer.
New-U Research Compounds supplies IGF-1 LR3 as a recombinant lyophilised powder at >99% HPLC purity, verified by independent third-party labs. All material is strictly for in-vitro and laboratory research. IGF-1 LR3 is structured protein material that is sensitive to repeated freeze-thaw cycles, so it is typically reconstituted in dilute acetic acid to limit aggregation and then aliquoted. It is not approved for human therapeutic use (mecasermin, the native rhIGF-1, is the approved drug for paediatric primary IGF deficiency) and is on the WADA Prohibited List. Nothing on this page is medical advice or a dose recommendation.
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