IGF-1 LR3
IGF-1 LR3 is a recombinant analogue of insulin-like growth factor-1 engineered for greater potency and a longer half-life, chiefly by reducing its binding to IGF-binding proteins. It is manufactured and marketed as a research-use-only reagent to stimulate cell growth in laboratory culture; it has not undergone human clinical development and is not an approved therapeutic.
Mechanism
In plain terms, it is a lab-made version of a natural growth factor, altered so it stays active longer and works more strongly on cells. Technically, Long R3 IGF-1 carries an arginine substitution at position 3 and a 13-amino-acid N-terminal extension; these changes markedly reduce its affinity for IGF-binding proteins, leaving more free peptide available to activate the IGF-1 receptor (a receptor tyrosine kinase) and downstream PI3K/Akt and MAPK signalling that drive cell proliferation and protein synthesis. This pharmacology is characterised in cell and animal systems, not in approved human therapeutics.
Regulatory Status by Region
- United States (FDA)Not approved for any human use; marketed as a research-use-only reagent, not for human administration. It is a distinct molecule from the approved recombinant human IGF-1 drug mecasermin (Increlex).
- Australia (TGA)Not on the Australian Register of Therapeutic Goods (ARTG); an unapproved substance with no registered therapeutic product.
- European Union (EMA)No EMA marketing authorisation; not an approved medicine in the EU.
- WADAProhibited at all times under Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics); insulin-like growth factor-1 (IGF-1) and its analogues are explicitly covered.