P21

P21 is a synthetic peptide derived from ciliary neurotrophic factor (CNTF) that retains neurotrophic activity while lacking the side-effects of the full CNTF protein. The compound was developed as a research tool for investigating CNTF receptor signalling without confounding full-length-protein effects.

Approximate molecular weight 2200 Da. ChEMBL ID CHEMBL3360826.

P21 engages the CNTF receptor complex (CNTFRα-LIFRβ-gp130) and triggers JAK/STAT3 signalling, which promotes neuronal survival, differentiation and synaptic plasticity. The fragment retains receptor-binding activity but lacks the systemic effects (weight loss, immunological activity) associated with full CNTF protein administration.

Investigated in preclinical models of neurodegenerative disease — particularly Alzheimer's-disease models where CNTF signalling has been implicated in neuronal survival — and in spinal-cord injury research.

Supplied as a research-grade reference standard for laboratory use only. Not a licensed medicinal product in the United Kingdom and not approved by the MHRA for human or veterinary administration. Sale is restricted to researchers, institutions and laboratory professionals; the compound must be retained within research premises. End-user compliance with the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 (where applicable) and local institutional biosafety policy is the responsibility of the buyer.