PLX-5622 is a selective inhibitor of the colony-stimulating factor 1 receptor (CSF1R), primarily used in research to deplete microglia, the resident immune cells of the central nervous system. It is widely applied in preclinical studies of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and ALS to investigate the role of microglia in disease progression. By crossing the blood-brain barrier and effectively reducing microglial populations, PLX-5622 enables researchers to study neuroinflammation, synaptic changes, and neuronal health in the absence of microglial activity. It is also used in cancer research to examine the impact of tumor-associated macrophages on tumor growth and immune response, particularly in glioblastoma and other CNS malignancies. The compound is typically administered orally in rodent models and has become a valuable tool for understanding the contribution of myeloid cells in various disease contexts.