Social media (SM) have fundamentally changed the way we exchange information, including how we communicate about health. The goal of this study was to describe current prevalence and predictors of SM use by analyzing nationally representative data from the 2019 Health Information National Trends Survey (HINTS). Multivariate logistic regression models examined the odds of engaging in four SM activities: visiting social networking sites, sharing health information on SM, participating in online support groups, and watching health-related videos. In 2019, approximately 86% of Internet users reported engaging in at least one SM activity. Younger age and female gender were associated with higher likelihood of engaging in all SM activities. No significant ethnic/racial disparities were observed for most SM activities, but Hispanics were found to be more likely to report watching health-related videos. Additionally, those with regular health care access were more likely to participate in online support groups. Previous HINTS survey cycles were also used to examine change in SM use over time, showing that general SM use has increased substantially since 2007, but the use of SM for health-related purposes has not increased to the same extent. The dynamic and evolving nature of SM makes systematic assessment vital. Knowledge of current SM use patterns could make health communication efforts more effective and equitable.