Background: Both type 1 and type 2 diabetes have detrimental effects on the central nervous system and increase the risk of cognitive disorders such as Alzheimer's disease. Additionally, there is a proposed condition called "type 3 diabetes" that refers to insulin resistance and impaired insulin signaling in the brain, leading to cognitive deficits similar to those seen in Alzheimer's disease. Diabetes leads to various changes in the CNS, including structural and functional alterations. Chronic high blood sugar levels, oxidative stress, inflammation, and vascular damage associated with diabetes contribute to neuronal damage and impaired synaptic plasticity. Alpha-lipoic acid (ALA) is a naturally occurring compound that acts as a powerful antioxidant. Conclusions: DM cause damage to CNS through increasing the risk of cerebrovascular diseases, promoting chronic low-grade inflammation, increasing oxidative stress, inducing Alzheimer's diseaseand diabetic encephalopathy. ALA protects against these effects through Improving Insulin Sensitivity, glucose utilization, antioxidant and anti-inflammatory properties. Keywords: Diabetic encephalopathy; ALA; Thioctic acid ;type 3 diabetes;Alzheimer’s disease