P21 (CAS 1246751-68-7), also known as Peptide 021 or P021, is a synthetic hexapeptide derivative with the molecular formula C27H42N6O8 and a molecular weight of 578.67 g/mol. Its structure, Ac-Asp-Gly-Gly-Leu-Ala-Gly-NH2 with a C-terminal adamantane modification, was derived from the most active region of ciliary neurotrophic factor (CNTF) through epitope mapping. The acetylated N-terminus confers resistance to aminopeptidase degradation, while the adamantylated glycine at the C-terminus incorporates a rigid lipophilic tricyclic diamondoid to increase blood-brain barrier permeability and resistance to exopeptidase cleavage. Produced via solid-phase peptide synthesis, P021 is associated with BDNF expression and neurogenesis-related signalling pathways in preclinical neuroscience research.

P21 has been investigated in preclinical neuroscience as a small-molecule CNTF mimetic with a mechanism centred on modulation of the CNTF/leukemia inhibitory factor (LIF) signalling axis and the BDNF–TrkB pathway. Published research from the originating laboratory has characterised P21 as acting through inhibition of LIF signalling and increased BDNF expression, with downstream activation of the BDNF/TrkB–PI3K/Akt pathway associated with inhibitory phosphorylation of GSK3β [1]. In vivo rodent studies have examined P21 in transgenic models of Alzheimer-type pathology, with published research documenting that chronic administration of P21 in the triple-transgenic (3xTg-AD) mouse model was associated with rescue of adult hippocampal neurogenesis and synaptic-plasticity markers and reduction of tau hyperphosphorylation [2], making P021 a reference compound in preclinical neuroscience research examining CNTF-derived peptide modulation of LIF/BDNF signalling and adult hippocampal neurogenesis in rodent models.

P21 is manufactured in a cGMP compliant, ISO9001 certified laboratory to a guaranteed purity of 98% or above. Every batch is independently tested using HPLC and MS-UPLC analysis before dispatch. Vials are vacuum sealed and stored in a temperature controlled, monitored cold storage system. Certificates of Analysis are available on request.

Sold strictly for in vitro research purposes only. Not for human consumption. Intended for use by qualified researchers in laboratory settings only.

Editorial Team

Dr. Martina Rossi, PhD

Scientific Contributor and Reviewer

Reviewed and approved 14 June 2026

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