 The study aimed to evaluate three single-session interventions, SSIs, embedded as cocoa mini-courses on Tumblr to improve hopelessness, self-hate, and the desire to stop self-harm behavior in teenagers. The SSIs were completed 6,179 times between March 2021 and February 2022, with high star ratings and completion rates relative to other digital self-help interventions. Paired T-Tests showed significant pre-post reductions in hopelessness and self-hate, and an increase in the desire to stop self-harm from before to after completing the SSIs. The results suggest that brief SSIs embedded within popular social platforms may be a promising and acceptable method for providing free, scalable, and potentially helpful mental health support on the web, particularly for teenagers without access to other mental health supports.