Reference
What is IGF-1 LR3?
IGF-1 LR3 (Long R3 IGF-1) is a modified form of insulin-like growth factor 1, a 70-amino-acid protein hormone. Two changes set it apart: the glutamic acid at position 3 is replaced with arginine (the "R3"), and a 13-amino-acid extension is added at the start of the chain (the "Long"), giving 83 residues in all.
Classification
| Type | Peptide |
| Chain length | 83 amino acid residues |
| Family | Insulin-like growth factor analogue |
| Origin | Developed in Adelaide, South Australia, in the early 1990s |
| Supplied as | Lyophilised powder in a sealed vial |
Both changes were made for laboratory work. Natural IGF-1 is held tightly by a family of binding proteins, and the analogue was designed to bind them far less, which is why it became a common reagent in cell-culture media. It is made by recombinant expression rather than chemical synthesis, and supplied by weight in micrograms or milligrams.
Where it sits by length
At 83 residues, IGF-1 LR3 is long enough to sit near the loose boundary where peptides start being called small proteins. The boundary is a convention, not a rule of chemistry — chains up to roughly fifty residues are generally called peptides.
What this page does not cover
Nothing here describes what IGF-1 LR3 does, what it is used for, or whether it is safe. We publish analytical results and ship parcels; we give no guidance on dosing, preparation or use, and that applies to our reference pages as much as to the product pages. The person to ask about any of that is a registered prescriber.
Related by family
More on IGF-1 LR3
Buy IGF-1 LR3 in NZ · What is a peptide? · Discovery timeline · All reference
