Rates of cardiovascular disease and diabetes are more than 2-fold greater in HIV infected people than the general population. Protease inhibitor booster antiretroviral therapy (PI-ART) which is used by ~50% of HIV infected people in the USA is an established risk factor for diabetes. Tauroursodeoxycholic acid (TUDCA), a naturally occurring bile salt, improves insulin sensitivity in HIV uninfected subjects, although the mechanisms for these benefits are unclear. This study will explore the hypothesis that TUDCA will improve insulin action in people with HIV who are receiving PI-ART. Further, this project will clarify the molecular mechanisms responsible for these improvements potentially benefiting society, irrespective of HIV status.