In Mexico, underprivileged adolescents have a higher than average teen pregnancy rate, lower use of contraceptives, and little access to reproductive health services. Yet, few evidence-based attempts to build more equitable, accessible, and available reproductive health services for disadvantaged adolescents than their counterparts have been made. The objective is to describe the design and development process of new content that has been integrated to work in synergy with an existing website to promote sexual and reproductive health among Mexican adolescents. We adopted a user-centered participatory action research approach. We developed a set of nine interactive activities that promote knowledge and skills on self-esteem, gender equity, self-efficacy, and decision-making; a chat with live counseling for healthy sexual and reproductive behavior; and a video with a message that highlights the importance of delaying motherhood. By incorporating this type of constructivist strategy, we seek to meet adolescents' needs more easily and improve the acceptability of interventions.