Social media has significantly broadened the scope of digital engagement, facilitating more dynamic and diverse interactions between humans and computers. These interactions are not standalone but interwoven within the broader framework of social institutions. These institutions shape the context in which social interactions occur, establishing the rules, expectations, and power dynamics underpinning these exchanges. Social institutions have been central in various significant topics where interactions through discourse among social media users have occurred. Similarly, when social media users interact in discussions about sensitive or taboo issues, social institutions subtly influence the conversation—often guiding it or being referenced in the background, even if they are not the primary focus. These advantages are evident in how members of a Philippine LGBTQIA+ subreddit engage with each other when discussing HIV. This study employed a qualitative approach grounded in Social Institutional Theory to explore the social institutions in HIV discussions within a Philippine LGBTQIA+ subreddit, r/phlgbt. The research extracted threads containing the term ‘HIV,’ yielding 3,496 interactions from the subreddit, including both original posts and comments posted from 2014 to 2024. The results revealed that there are 264 relevant interactions, with health and the Internet being the social institutions most prominently mentioned in the threads. Furthermore, the intersection of health and Internet institutions in the discussions presents the existence of techno-social institutions. Users provide guidance with technological support and utilize the same technological advancements to support their claims. Lastly, users would also deter others from relying solely on Internet-based information.