IGF-1

IGF-1 (Insulin-like Growth Factor 1, also called Somatomedin C) is a 70-residue single-chain protein with three intra-chain disulfide bonds. It is the principal downstream mediator of growth-hormone action — circulating IGF-1 is predominantly synthesised in the liver in response to pituitary growth- hormone signalling. Researchers most commonly investigate the "Long R3" variant (Long R3 IGF-1, LR3 IGF-1), which has an N-terminal MFPAMPLSSLFVNGPRTLCGAELVDALQFVCGDRGFYFNKPT extension and an arginine-for-glutamate-3 substitution that dramatically reduces its affinity for the IGF-binding proteins (IGFBPs).

CAS 67763-96-6 (native IGF-1), molecular formula C₃₃₁H₅₁₂ N₉₂O₉₃S₇, molecular weight 7649 Da. Wikidata QID Q72483268, ChEMBL ID CHEMBL4297954.

IGF-1 binds the IGF-1 receptor (a tyrosine kinase structurally related to the insulin receptor), triggering autophosphorylation and downstream PI3K/Akt and Ras/MAPK signalling. The pathway mediates cellular proliferation, anti-apoptotic signalling and protein synthesis in target tissues — particularly skeletal muscle and connective tissue.

The Long R3 variant's reduced IGFBP affinity means it circulates predominantly in unbound (active) form, producing a substantially longer effective half-life than native IGF-1 in research protocols.

Used as a reference standard in growth-factor signalling research, skeletal-muscle hypertrophy models, and regenerative-medicine cell-culture protocols where IGF-1 is commonly included as a growth-supplement component.

Human growth hormone and its synthetic analogues are Class C controlled drugs under the Misuse of Drugs Act 1971 (Schedule 4 Part II) when intended for human administration. NMChem supplies these compounds strictly as research-grade reference standards for laboratory characterisation and in-vitro / preclinical research. Material must be retained within licensed research premises and is not for human or veterinary therapeutic use. Buyers are responsible for compliance with the Misuse of Drugs Regulations 2001 and any institutional controlled-substance licensing requirements.