Social media can be a platform to spread misinformation and reinforce potentially harmful norms in the interest of commercial actors. There are norms related to obesity that commercial actors promote such as "obesity is an individual problem" and the "pharmaceuticalization of obesity". In this study, we assess the quality of information about semaglutide, and the descriptive norms related to its use as levers of commercial practices in social media. We carried out a content analysis of Spanish speaking TikTok videos published between January 2022 and November 2023. We used the DISCERN instrument to assess the quality of information and classified the social norms disseminated through the videos and the narrating voices. The overall quality of information was low, with a mean DISCERN score of 29.8 out of 75. Although healthcare professionals and professional communicators performed slightly better compared to other voices, critical aspects of good health communication were often lacking; 155 videos (71%) did not mention any risk related to the use of semaglutide and only 11.9% of videos mentioned one or more serious risks. In 85% of videos, obesity was depicted as an individual problem. About half of the videos normalized the use of semaglutide and 79% of videos promoted the pharmaceuticalization of obesity by mentioning losing weight as a benefit of using semaglutide but not mentioning the need to make lifestyle changes. The combination of poor-quality health information and the promotion of potentially harmful norms related to semaglutide use is a public health concern. Further research on the commercial determinants of health in the context of semaglutide use is needed, as well as actions to mitigate the risks of misinformation and harmful health-related norms.