Background Avatars have been used as tools for communication in various fields. However, the characteristics of avatars useful for health communication remain unclear. This study aimed to examine the impact of medical avatars (MAs) on health communication. Methodology An anonymous questionnaire survey was conducted among individuals aged 18-59 years. Participants were randomly assigned to view one of four avatar-based videos (medical male, nonmedical male, medical female, or nonmedical female avatar). In this study, MAs were defined as those wearing white coats, while nonmedical avatars (NAs) wore hoodies. Total scores for perceived persuasiveness of the video, avatar acceptability, and exercise self-efficacy were then compared between the MA and NA groups. Results Overall, 309 participants were included in the analysis, with 160 (51.8%) classified into the MA group and 149 (48.2%) into the NA group. The MA group had higher scores for persuasiveness and acceptability than the NA group. In the subgroup analysis based on avatar experience among individuals with avatar experience, the MA group had higher persuasiveness and acceptability scores than the NA group
however, no significant difference was observed among individuals without avatar experience. Conclusions In health communication, avatar appearance may impact the persuasiveness and acceptability of the videos. The results of this study indicate that avatars wearing white coats were perceived as more persuasive and acceptable by the participants.