In the central nervous system (CNS), GLP-1 and GLP-1R agonists are diffused into the cerebrospinal fluid (CSF) and the brain as demonstrated in rodent models (Wang et al., 2015), and increased GLP-1 concentration in the brain is thought to influence brain function in the hippocampus (Kastin et al., 2002
The 2.5mg dose is the standard starting dose for tirzepatide
However, feeding these mice with high fat jelly diet prevented their gastrointestinal problems and their death was reported to be due to TDP-43 pathology mediated degeneration, and not due to gastrointestinal problems 75,76
10.1016/j.biopha.2022.113360 Biomed
doi: 10.3389/fimmu.2026.1761421 Received 05 December 2025 Revised 31 January 2026 Accepted 04 February 2026 Published 24 February 2026 Volume 17 - 2026 Edited by Qiushui He, University of Turku, Finland Reviewed by Jan Josef Stepan, Charles University, Czechia Namrata Anand, University of Chicago Medical Center, United States Updates Copyright 2026 Liu, Lu, Bai, Han, Zha and Jiang
10.1016/S0969-2126(99)80023-9 Structure