IGF-1 LR3
Also: Long R3 IGF-1, LR3 IGF-1, IGF-1 Long R3, Long Arg3 IGF-1, rh-IGF-1 LR3
This profile summarizes research context only. It is not medical advice and does not describe how to use this compound in humans or animals — no dosing, administration, or protocols. Learn more
IGF-1 LR3 (Long R3 IGF-1) is a recombinant analog of insulin-like growth factor 1, modified so that it binds IGF-binding proteins (IGFBPs) less tightly than the native hormone. In the research literature it is described primarily as a cell-culture and bioprocess reagent and as a tool for studying IGF-1 receptor signaling, where it is reported to show greater in-vitro potency than native IGF-1. It is not an approved drug, and the available evidence is largely preclinical and mechanistic rather than clinical. Terminology and material identity vary between sources and should be verified editorially.
Mechanism as described in the literature
IGF-1 LR3 (Long R3 IGF-1) is a recombinant analog of insulin-like growth factor 1, described in the research literature as carrying an arginine-for-glutamate substitution at position 3 together with a 13-residue N-terminal extension. These modifications are reported to substantially reduce the molecule's affinity for insulin-like growth factor binding proteins (IGFBPs), which in cell-culture systems is associated with a longer apparent half-life and greater in-vitro potency relative to native IGF-1.
Mechanistically, IGF-1 and its analogs are reported to act primarily as agonists at the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase that signals through the PI3K/Akt and MAPK pathways, with some cross-reactivity at the insulin receptor also described. Most of this characterization comes from in-vitro and biochemical work; these are mechanistic observations and should not be read as claims about effects in animals or people. The extent to which such mechanisms translate to whole-organism or human contexts remains uncertain and requires careful interpretation due to study-design and translation limitations.
Research areas
- Use as a serum-free cell-culture and bioprocess media supplement in laboratory settings
- IGF-1R and downstream PI3K/Akt and MAPK signaling biology characterized in vitro
- Comparative pharmacology of IGFBP-resistant IGF-1 analogs versus native IGF-1
- Receptor-binding and structure-activity characterization at the biochemical level
- Analytical and anti-doping detection method development reported in the literature
Documentation notes
References
Frequently asked questions
What is IGF-1 LR3?+
It is a laboratory-made analog of insulin-like growth factor 1 (IGF-1), described as carrying a position-3 substitution and an N-terminal extension. In the research literature it is discussed mainly as a cell-culture reagent and a tool for studying IGF-1 receptor signaling. RUO Report is an educational resource and does not provide any guidance on use.
How is IGF-1 LR3 different from native IGF-1?+
The modifications are reported to lower its binding to IGF-binding proteins (IGFBPs), which in cell-culture systems is associated with a longer apparent half-life and higher in-vitro potency than native IGF-1. These are mechanistic, in-vitro observations and should not be read as claims about effects in animals or people.
Is the evidence for IGF-1 LR3 strong?+
No. Most documentation is preclinical (in-vitro, biochemical, or animal-model) or relates to its use as a research reagent. Human data are limited and require careful interpretation due to study-design and translation limitations. References in this profile are intentionally left for editorial verification.