Thymosin &bgr;4 can be used to treat neuronal and brain injuries that are accompanied by neuronal cell death or injury, including injuries caused by stroke or trauma and injuries caused by neurological and neurodegenerative disease. In particular, stroke and multiple sclerosis are examples of conditions which may be ameliorated by treatment with thymosin &bgr;4. Thymosin &bgr;4 has been found to restore neurological tissue through several effects on several neurological parameters which are improved by administration of thymosin &bgr;4 to a subject in need of neurological tissue restoration. For example, thymosin &bgr;4 improves axonal myelination, migration of neural progenitor cells, neural progenitor cell proliferation, differentiation of neural progenitor cells into mature neurons, differentiation of neural progenitor cells into mature glia, nerve regeneration, and brain remodeling at locations of brain injury.