The investigators will pilot test an intervention to use a mobile application ("app") to improve HIV self-testing (HST) with high-risk men in China. Sixty participants will be randomly assigned to an intervention group - which involves access to a mobile app-based HIV testing health promotion and risk reduction program - versus control. Participants will be evaluated at baseline and at 6-month follow up with respect to HST and changes in sexual risk behaviors.

Men who have sex with men (MSM) have emerged as one of the fastest growing HIV risk populations in China, the world's most populous country. Studies in China report that MSM have low rates of HIV testing, low use of HIV prevention services, and high levels of unprotected sex with both male and female partners. Stigma presents one of the critical barriers to engaging MSM in HIV testing and prevention interventions, as many MSM in China avoid health service facilities that require face-to-face disclosure of their same-sex behaviors. Because HIV testing is a crucial opportunity for HIV prevention and represents the first step on the continuum of care, efforts to improve rates of HIV testing among MSM in China can contribute to reduced risk for HIV transmission and enhanced public health outcomes in this population.

For high-risk MSM in China, HIV self-testing (HST) offers a compelling strategy for achieving higher levels of HIV testing, due to the removal of barriers associated with traditional forms of in-person, clinic-based HIV testing. HST allows individuals to self-administer the HIV rapid diagnostic test in a private setting, which can detect for the presence of HIV-1/2 antibodies. The overarching goal of this research investigation is to improve the implementation science of HIV self-testing (HST) as a public health strategy to increase HIV testing among populations with low testing rates.

The investigators propose using a mHealth approach to support the implementation of HST. Specifically, the investigators hypothesize that incorporating mobile application- or "app"-based behavioral risk reduction messages with HST can preserve the privacy and comfort associated with self-administered testing, while also allowing for individuals to receive timely information and motivational cues to take the crucial next steps following their HST results - i.e., to test repeatedly, to reduce their behavioral risks for HIV transmission, and to seek appropriate referral services as needed.

This research will examine the acceptability and preliminary effects of HST linked with app-based behavioral risk reduction messages in a sample of high-risk MSM in China. In this pilot study, the investigators will test the primary hypothesis that the combination of HST plus mobile app-based risk reduction messaging compared to HST alone will increase HST re-testing and reduce sexual risk behavior in the next 6 months.

Inclusion Criteria:

• Age 18 or older
• Biological male
• Unprotected anal sex during the past 6 months
• Current resident in Hefei (city), China
• HIV-negative or HIV-status unknown
• Possess a mobile "smart" phone
• Not planning to relocate from study location

Exclusion Criteria:

• HIV positive at enrollment
• Self-report coercion to participate