IGF-1 LR3
Long Arg3 IGF-1 analog with extended half-life, studied for anabolic and tissue-growth pathways.
Research overview
IGF-1 LR3 is a long-acting, synthetic analogue of endogenous Insulin-like Growth Factor 1 (IGF-1). It is a modified version of the 70-amino acid IGF-1 polypeptide, featuring two specific alterations: Long R3 — a substitution of an Arginine (R) for the naturally occurring Glutamic Acid (E) at the third position; and an addition of a 13-amino acid extension peptide at its N-terminus.
The primary purpose of these modifications is to dramatically reduce the peptide's binding affinity to the Insulin-like Growth Factor-Binding Proteins (IGFBPs). In the body, IGFBPs bind to native IGF-1, which regulates its availability and short half-life. By evading this binding, IGF-1 LR3 remains free and active in the bloodstream for a much longer period, significantly increasing its bioavailability and potency.
Like native IGF-1, it binds to the IGF-1 receptor on cells, promoting potent anabolic (growth) and hyperplastic (cell proliferation) effects. It is an experimental compound used in laboratory research to study the effects of sustained IGF-1 activity.
Peer-Reviewed Research (PubMed)
Selected landmark / highly-cited studies indexed on PubMed.
- 1.Long R3 IGF-I: a more potent and biologically active analog of insulin-like growth factor ITomas FM, et al. — Journal of Endocrinology, 1991
- 2.IGF-I and IGF-binding proteins in muscle wasting and recoveryFrost RA, Lang CH. — Endocrinology, 2003
- 3.Insulin-like growth factor I as an anabolic agentYakar S, Adamo ML. — Endocrinology and Metabolism Clinics, 2012
Studied benefits
- Extended half-life vs native IGF-1
- Lower IGFBP binding affinity
- Studied for tissue hypertrophy
- Activates IGF-1 receptor signaling
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