The aim of this study was to investigate the prevalence of performance- and image-enhancing substances (PIES) use, and factors related to this, among a representative sample of the general Swedish population aged 16–25. We used a quantitative cross-sectional self-report design to examine prevalence and possible relationships between PIES use and socio-demographics, physical activity, attitudes towards muscle building and doping, friends’ use, body image, and body modification. Approximately 12% of the respondents reported that they used or had used PIES. A logistic regression analysis pointed out the importance of the social context – friends who used PIES, how body image affected social life, and how others viewed one's body – as more important factors for using PIES than attitudes towards muscle building and doping. Taken together, these results indicate a need to pay attention to the use of PIES among young people as a potential public health problem.