[Editorial] A wake-up call: the second Commission on adolescent health

9 years ago, The Lancet published the first Commission on adolescent health, which argued for adolescence as a key stage of development in the life course that has been largely neglected by the global health community. When a second Commission started its work in 2021, in the middle of the COVID-19 pandemic, its goal was to focus on accelerating the implementation of the first Commission's recommendations towards the Sustainable Development Goals and beyond, to realise the so-called triple dividend: the immediate benefits for adolescents’ health and wellbeing, for their health and wellbeing as adults, and for that of future generations.