IGF-1 LR3 comes up often once the growth-hormone axis enters the conversation, but what exactly is it and why not just natural IGF-1? In this guide we explain, research-only, what IGF-1 LR3 is, how it differs from the natural molecule, and which research themes it is studied within.
IGF-1 LR3 is a modified form of insulin-like growth factor 1, with an extra arginine (Long Arg3) that gives the molecule a longer half-life than natural IGF-1. It is studied within the growth-hormone axis. For research use only, ≥99% pure with a COA per batch.
What is IGF-1 LR3?
IGF-1 LR3 is a modified form of insulin-like growth factor 1 (IGF-1), a growth factor the body produces itself, mainly in the liver under the influence of growth hormone. New to peptides? First read what peptides are.
Why “LR3” and not just IGF-1?
The addition “LR3” (Long Arg3) refers to an extra arginine amino acid at the start of the chain, which weakens binding to IGF-binding proteins in the body. Natural IGF-1 is quickly bound and broken down by those carrier proteins, whereas IGF-1 LR3 therefore stays “free” and more stable for longer as a research subject — a practical property for reproducible research.
IGF-1 LR3 and the growth-hormone axis
IGF-1 LR3 is studied further down the same signalling pathway as growth hormone, which makes it a recurring subject alongside GHRH analogues and GHRPs. The full breakdown of that family is in the hub growth-hormone peptides, with growth hormone itself explained in what is HGH and the GHRH analogue tesamorelin. Want to know why these peptides are also widely searched within the bodybuilding community? Read peptides for muscle growth.
Purity and documentation
Reproducible research with IGF-1 LR3 requires material with verified purity and full traceability. Every batch at Peptide Lab is tested by Janoshik Analytical at ≥99% purity by HPLC and mass spectrometry, with a public certificate per lot number. The product is supplied as a lyophilised powder — calculate the reconstitution ratio with the reconstitution calculator.
This information is general and intended solely for a research context. Peptide Lab supplies IGF-1 LR3 for laboratory and research purposes only. Not for human or animal consumption, not a medicine and not medical advice.
Frequently asked questions about IGF-1 LR3
What is IGF-1 LR3?
IGF-1 LR3 is a modified form of insulin-like growth factor 1 (IGF-1), a naturally occurring growth factor. The 'LR3' modification (Long Arg3) gives the molecule a longer half-life than natural IGF-1, making it more usable as a research subject.
What is the difference between IGF-1 LR3 and natural IGF-1?
Natural IGF-1 is rapidly broken down and bound by binding proteins in the body, which makes it hard to use as a stable research subject. IGF-1 LR3 has an extra arginine at the start of the chain and binds less well to those binding proteins, keeping it 'free' and available for longer in research.
What is IGF-1 LR3 studied for in research?
IGF-1 LR3 is studied within the same signalling pathway as growth hormone, further down the axis. It is a recurring subject in physiological research into cell growth and differentiation. This concerns preclinical research, without health or usage claims.
Is IGF-1 LR3 pure at Peptide Lab?
Yes, IGF-1 LR3 is lab-verified at ≥99% purity by HPLC and mass spectrometry, with a public Janoshik certificate per batch. For research purposes only.
