Human brain metabolism was investigated using hyperpolarized [1-13C]pyruvate and [2-13C]pyruvate in vivo. Each subject received hyperpolarized pyruvate intravenously with a 45-min interval between the injections. [1-13C]lactate and [13C]HCO3– were consistently detected from hyperpolarized [1-13C]pyruvate. [5-13C]Glutamate was measured from hyperpolarized [2-13C]pyruvate. The levels of production and relative intensities of the 13C-labeled metabolites were reproducible.