The corpus callosum (CC) is a wide and thick nerve tract in the brain. It is the largest white matter structure in the human brain, measuring approximately 250mm in length, and consisting of 200-300 million myelinated axons. According to the World Health Organization (WHO), the world's population is getting older. Aging is one of the main risk factors for neurodegenerative diseases. Brain aging involves mitochondrial dysfunction, dysregulated energy metabolism, altered neuronal activity, and inflammation. Changes in white matter metabolism during aging are poorly understood. In this study, we analyzed the CC of young (2-4 months) and aged (18-24 months) mice, focusing on metabolism. First, we examined glial markers in the CC to study astrocytes and microglia during aging. Reduced levels of Neurofilament (NFH, axon marker) and Myelin Basic Protein (MBP, myelin marker) in the aged CC suggested a loss of myelinated axons during aging. Metabolomic analysis were performed using gas chromatography-mass spectrometry (GC-MS). The aged CC exhibits lower levels of monosaccharides such as glucose, which is related to the hypometabolism during aging. In addition, the aged CC exhibited reduced levels of fatty acids and myelin-related lipids. This is consistent with immunofluorescence studies showing reduced levels of myelin in aged axons. Therefore, during aging, lower levels of myelin could be related to lower levels of fatty acids essential for myelination. Also, lower levels of energy substrates such as glucose could be related to the loss of axons. Thus, impaired metabolism could be related to the loss of white matter during aging.