Background <p>Nutrition misinformation spreads rapidly on social media. Young adults particularly rely on influencers and platforms, such as TikTok, for nutrition information. This study examined young adult TikTok users’ trust in nutrition information and nutrition influencers, exploring whether influencer qualifications and message accuracy influence trust.</p> Methods <p>We conducted an online experiment using Prolific and Centiment. A total of 1,035 TikTok users aged 18–26&#xa0;years were recruited from four countries (USA, UK, Australia, Canada), with 1,016 included in the final analysis. Participants were randomly assigned to view one of six TikTok videos manipulating (1) influencer qualification (qualified vs neutral vs not qualified) and (2) information accuracy (accurate vs misinformation). Outcomes were self-reported trust in the influencer and trust in the message content, measured using validated multi-item scales. Differences across conditions were analysed using factorial ANCOVA models in SPSS.</p> Results <p>Trust in the influencer and trust in the message differed by qualification condition, with the highest trust observed when the influencer reported a nutrition qualification. Trust in both outcomes was also higher when the video contained accurate information compared with misinformation, with mean differences across conditions ranging from approximately 0.47 to 0.50 points on the scale. Post hoc analyses indicated lower trust in both the influencer and the message among Canadian participants relative to other countries.</p> Conclusions <p>Influencer qualifications and information accuracy independently increase young adults’ trust in TikTok nutrition content. These findings support encouraging qualified nutrition professionals to prominently disclose relevant credentials, ensure accuracy in original posts, and actively counter inaccurate nutrition content shared by others.</p>