Metformin is currently first line therapy for type 2 diabetes (T2D). The mechanism of action of metformin involves activation of AMP-activated protein kinase (AMPK) to enhance mitochondrial function (for example, biogenesis, refurbishment and dynamics) and autophagy. Many neurodegenerative diseases of the central and peripheral nervous systems arise from metabolic failure and toxic protein aggregation where activated AMPK could prove protective. Areas covered: The authors review literature on metformin treatment in Parkinson's disease, Huntington's disease and other neurological diseases of the CNS along with neuroprotective effects of AMPK activation and suppression of the mammalian target of rapamycin (mTOR) pathway on peripheral neuropathy and neuropathic pain. The authors compare the efficacy of metformin with the actions of resveratrol. Expert opinion: Metformin, through activation of AMPK and autophagy, can enhance neuronal bioenergetics, promote nerve repair and reduce toxic protein aggregates in neurological diseases. A long history of safe use in humans should encourage development of metformin and other AMPK activators in preclinical and clinical research. Future studies in animal models of neurological disease should strive to further dissect in a mechanistic manner the pathways downstream from metformin-dependent AMPK activation, and to further investigate mTOR dependent and independent signaling pathways driving neuroprotection.