In South Africa, HIV transmission is fueled by a cycle: young adult men transmit HIV to younger female partners, who in turn grow up and transmit it to their male peers. In many cases, these men are especially reluctant to use existing HIV services, making it unlikely that they learn their HIV positive status and initiate treatment. Break the Cycle uses qualitative and quantitative market research to understand the drivers and barriers for young men’s testing and linkage decisions and behaviors. This information is used in tandem with human-centered design to adapt existing interventions so that they better overcome these barriers, helping more at-risk men to access the prevention and treatment services they need.