Vitamin C (ascorbate) is well established as an essential nutrient that functions as an antioxidant. Since it is present in the human brain at detectable concentrations, this study was designed to detect and quantify ascorbate in the human brain in vivo using 1H NMR spectroscopy (MRS). Ascorbate was consistently detected in all five study subjects, and was measured using MEGA-PRESS difference editing. The in vivo resonance pattern was consistent with that of ascorbate based on position, line width, peak pattern, and relative intensity. Metabolites with a potential for coediting were assessed using phantom solutions. The putative resonances of myo-inositol, lactate, glycerophosphocholine, phosphocholine, and phosphoethanolamine were detected at positions distinct from those of ascorbate. This study represents the first in vivo detection of vitamin C in the human brain using 1H MRS. A concentration of 1.3 +/- 0.3 micromol/g (mean +/- SD, N = 4) was estimated.