Background: Suicide is the second-leading cause of death among 15–29-year-olds and Instagram is one of the most popular and fastest-growing social media platforms among this age group. A previous study presented preliminary evidence for suicide-related “subliminal messages” on Instagram, defined as very brief presentations of suicide-related content in video posts that users have no conscious awareness of. Aim: A systematic quantitative study was pending. Method: We conducted a quantitative content analysis of 100 Instagram video posts. A frame-by-frame coding procedure allowed for an assessment of whether suicide-related content was depicted in very brief segments, even when this content could not be consciously recognized when watched at regular speed. Results: Analysis indicates that a substantial amount of suicide-related content is presented in very brief shots. We identified 67 very brief shots that appeared in 21 video posts. Of interest, 13 of these video posts presented more than one very brief suicide-related shot. Limitation: The subjective threshold of conscious awareness differs inter-individually. This complicates the operationalization of subliminal messages. Conclusion: Subliminal messages are ethically highly problematic. There is a need for a greater awareness of possible suicide-related subliminal messages on Instagram.