Methamphetamine (MA) addiction is a public health concern that causes substantial harm to individual users, and imposes an economic burden in the U.S. totaling up to $48.3 billion annually. This study proposes to address a critical aspect of this problem: the lack of any proven, FDA-approved pharmacological treatments for MA users. The proposal combines an intervention designed to improve energy metabolism in the brain, and a neuroimaging technique capable of measuring the neurochemicals that represent cerebral bioenergetic function. The study will replicate and extend a key neuroimaging finding from the investigators recent MA studies: that MA users have decreased phosphocreatine (PCr) levels in the brain, compared to healthy volunteers. Phosphocreatine is the substrate reservoir for the creatine kinase reaction, which reversibly converts PCr into adenosine triphosphate (ATP), the brain's major energy supply, and creatine. Neuronal energy demands are met through a shift in reaction equilibrium, which is designed to maintain the concentration of ATP constant. Research results from the investigators recent study also showed that female MA users have lower brain PCr levels compared to male users. These findings join the converging lines of evidence that MA use is associated with mitochondrial dysfunction, i.e. deficient energy metabolism, in the brain. Frequently, MA users also experience depression, as well as cognitive deficits. Interestingly, both of these entities are also linked to mitochondrial dysfunction in the brain.