What it is
A synthetic 83-amino-acid analog of insulin-like growth factor 1 with an N-terminal 13-residue extension and an arginine-3 substitution. Supplied as a lyophilized powder.
How it works
Agonist of the IGF-1 receptor. The arginine-3 substitution and N-terminal extension dramatically reduce binding to IGF binding proteins, prolonging free circulation and bioactivity relative to native IGF-1.
Where it's used
Used historically as a research reagent and in cell culture. Studied in preclinical research for IGF-1 receptor signaling.
Regulatory status
Not FDA-approved; research compound.
Reconstitution
Supplied as a lyophilized powder requiring reconstitution with bacteriostatic water or an acidic diluent prior to use.
Tracking it
IGF-1 LR3 is injectable, so two things matter in a log: when you dosed and where. Rotating sites and writing both down prevents the classic “did I already pin the left side?” problem. with a half-life of about 20 hours, a dose log also lets a tracker model the relative amount still in your system between doses.
Source
Public reference
Last reviewed 2026-06-11