Dissolution dynamic nuclear polarization has enabled real-time metabolic imaging in both pre-clinical and clinical research applications. However, pre-clinical studies have provided evidence that inflowing metabolites can bias measurements in a number of organs. In this work, we explored the impact of inflowing lactate spins on quantitative hyperpolarized pyruvate 13C MRI of the human brain in a healthy volunteer. We provide evidence in a healthy volunteer that by pre-saturating inflowing lactate to address this confounding factor, kPL values in the brain were reduced by ~15%. Further studies will increase the sample size to better characterize this effect.