Background <p>Social media use is a risk factor for eating and body image disturbances. The overlap between social media and eating and body image disturbances is particularly concerning in the Chinese context given an estimated billion active social media users in China, especially among females. This highlights the need for scalable, culturally adapted prevention and intervention strategies. This study developed and evaluated two online, self-guided, single-session interventions (SSIs), including a Media Literacy Intervention (MLI) and a Body Functionality-focused expressive writing Intervention (BFI), alongside waitlist controls, and examined their ability to improve body image among adult female Chinese social media users with eating disorder (ED) symptoms.</p> Methods <p>A total of 204 female social media users with ED symptoms were recruited via Xiaohongshu (Little Red Note) and randomized to the MLI (<i>n</i> = 68), BFI (<i>n</i> = 68), or waitlist control group (<i>n</i> = 68). Primary outcomes included measures of negative and positive body image. Secondary outcomes included a range of measures including ED psychopathology and psychological distress. Assessments were conducted at baseline, 1-week post-intervention, and 4 weeks after baseline.</p> Results <p>Both MLI and BFI interventions significantly outperformed the waitlist control on primary and secondary outcomes. The two interventions demonstrated comparable efficacy across most domains, except for eating flexibility, where BFI yielded greater improvements. Intervention uptake was high (93%), and most participants (95%) reported they would recommend the intervention to others.</p> Conclusions <p>SSIs show promise as accessible, acceptable, and effective tools for improving body image and reducing ED symptoms among Chinese female social media users with ED symptoms. Future research should conduct larger-scale studies to examine their effectiveness and long-term impact.</p>