Dietary supplements are widely advertised and the market is expanding worldwide. Research suggests that dietary supplement advertising may lead consumers to make inappropriate health-related decisions, to express behaviors such as overdosing, and to neglect healthy lifestyle behaviors. We conducted a content analysis of video advertisements for dietary supplements and described the content of advertisements with high numbers and frequent views. We analyzed 82 video advertisements on YouTube that promoted fat-reduction effects. We extracted 22 themes and classified them into 10 categories. The categories with the highest numbers of advertisements were “Exemption” (i.e., consuming the product frees the audience from refraining from binge eating) (20 ads, 24.4%) and “Health Concerns” (i.e., the product intake solves the health concerns of the audience) (19 ads, 23.2%). These advertisements may stimulate negative audience attitudes toward appropriate health behaviors. The category with the most frequent views was “Lifestyle” (i.e., adding product intake to a healthy lifestyle) (3,035,298 views). “Lifestyle” advertisements portray physical activity in a positive light and may promote appropriate health behaviors in the audience. We discuss the possible effects of the advertisements on audiences and consider issues for future research and practice.