Project Summary/Abstract The United States alcoholic beverage market topped $210 Billion in 2014, selling enough alcohol for each American to consume 9.2 liters (2.4 gallons) of pure alcohol in 2013. Due to alcohol consumption's long history and ample financial interest, there has been a great deal of research around alcohol and the benefits and detriments to consuming it. Despite the commonality of alcohol consumption and the ability for users to abuse the intoxicant, there remains a stigma around monitoring blood alcohol content (BAC) in a public forum (e.g. breathalyzers by police officers and breathalyzer controlled automobile ignitions). This stigma generally holds true even when part of a clinical study or while seeking help for an addiction. Thus, there is still a need for a BAC monitoring device that remains out of site or can be camouflaged into everyday items (e.g. clothing, jewelry, accessories), which has yet to be met be current systems. Near-infrared spectroscopy (NIRS) has been used by Vivonics to monitor and report a number of physiologically relevant parameters. Studies have shown the ability to use near-infrared wavelengths to estimate the blood alcohol concentration with a low error of 0.0049% BAC (legally intoxicated BAC is 0.08). The proposed effort will apply this approach but tailor implementation in a way that enables a miniaturized, wearable device which is accurate despite variations in physiology. Utilizing this concept, the goal of the proposed Phase I effort is to develop an accurate and temporally resolute BAC monitoring benchtop prototype. The overall goal of the Phase I effort is to demonstrate feasibility of the miniaturized NIRS approach, paving the way for human subject testing in Phase II. The long term goal of this program is to deliver an accurate and temporally resolute wearable BAC monitoring device that substantially improves subject compliance in clinical and academic research. The proposed program would not only benefit the research community, providing a tool to better understand how alcohol dose and frequency impacts physiological and physiological health, but would also benefit the general public on a larger scale by translating the findings from the research community into more responsible and healthy alcohol consumption practices.