Cellular signaling research peptides in this category are studied for their interactions with intracellular and intercellular communication pathways. IGF-1 LR3 — the primary compound in this category — is a recombinant analogue of insulin-like growth factor 1 with an arginine substitution at position 3 and an N-terminal extension that reduces binding to IGF binding proteins. This modification extends its half-life relative to native IGF-1, making it useful in studies of IGF-1 receptor activation and downstream signaling. Research applications include in vitro models of cell proliferation, differentiation, and survival signaling. Supplied as lyophilized powder with purity >99% verified by HPLC. For in vitro laboratory research use only.