Data on food supplement (FS) consumption profiles are scarce. This study aims to characterise FS consumption among Portuguese adults and identify personal, social, professional, and health-related factors influencing FS use. A cross-sectional study was conducted using an online questionnaire between July and September 2023. The participants were categorised into healthcare professionals (supplement users and non-users, i.e., HPS and HPnS) and non-healthcare professionals (supplement users and non-users, i.e., nHPS and nHPnS). Group distributions were compared using the χ