CARNS1 (carnosine synthase 1) is an ATP-dependent enzyme that catalyzes the synthesis of histidine-containing dipeptides, primarily carnosine and homocarnosine 1. The enzyme is preferentially expressed in fast-twitch skeletal muscle fibers and brain oligodendrocytes 1. CARNS1 plays crucial neuroprotective roles, particularly in neuroinflammation and neurodegenerative diseases. In multiple sclerosis, CARNS1 expression diminishes in demyelinated lesions but returns during remyelination, with CARNS1 deficiency exacerbating neuroinflammation and clinical symptoms 2. The enzyme is also reduced in aging and Parkinson's disease, particularly affecting oligodendrocytes 3. CARNS1 deficiency in aged mice causes hyperactivity and depression-like behaviors with elevated corticosterone levels 4. Beyond neurological functions, CARNS1 demonstrates tumor suppressor properties in breast cancer, where its downregulation correlates with poor prognosis and reduced survival 5. Additionally, muscle-derived CARNS1 provides radioprotection by generating carnosine, which protects hematopoietic stem cells through the carnosine/Slc15a2-p53 axis 6. The enzyme's broad tissue distribution and involvement in multiple pathological processes highlight its significance in maintaining cellular homeostasis and protecting against various diseases.