What Is IGF-1 LR3? Growth Factor Research Guide
An overview of IGF-1 LR3 — a long-acting IGF-1 analogue — covering how it is studied in growth and cell research, its potency and prohibited-in-sport status, and its research-use-only status in the UK.
7 min read · Published 2026-06-23
What Is IGF-1 LR3?
IGF-1 LR3 (Long R3 IGF-1) is a modified analogue of insulin-like growth factor 1. An amino-acid substitution and a 13-residue N-terminal extension reduce its binding to IGF binding proteins and extend its activity relative to native IGF-1, making it a potent tool compound in cell-biology research.
Research use only. This material is supplied for in-vitro laboratory research. It is not a medicine and is not for human or veterinary consumption, administration, or therapeutic use.
How IGF-1 LR3 Is Studied to Work
In research IGF-1 LR3 acts at the IGF-1 receptor and is used to study growth-factor signalling, cell proliferation and differentiation in culture. Because it is a potent growth factor, it is handled as a specialised laboratory reagent.
Evidence, Safety & Regulatory Status
IGF-1 LR3 is not an approved medicine in the UK and is supplied for laboratory research only. As a growth factor it is also a prohibited substance in sport under World Anti-Doping Agency (WADA) rules. Potent signalling reagents of this type warrant careful, compliant laboratory handling.
Research Handling & Quality
As a lyophilised (freeze-dried) peptide it is typically stored frozen and reconstituted with bacteriostatic water for in-vitro work — see our reconstitution guide and storage guide. Identity and purity should be verified against a batch-matched Certificate of Analysis (COA) with HPLC and mass-spectrometry data. View igf-1-lr3 product details and COA.
Frequently Asked Questions
Is IGF-1 LR3 approved in the UK?
No. It is supplied for laboratory research use only and has no UK marketing authorisation.
Why is IGF-1 LR3 'long-acting'?
Structural modifications reduce its binding to IGF binding proteins and extend its activity compared with native IGF-1.
Is IGF-1 LR3 banned in sport?
Yes — as a growth factor it is prohibited under WADA rules. Research-grade material is for laboratory use only.
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