We must invest now in digital health interventions for adolescents. The current health status of Australian adolescents is concerning. Over 80% are not meeting national dietary or physical activity guidelines, and rates of mental ill-health are rising, with around three-quarters experiencing depression or anxiety symptoms. Yet, as a nation, we are not investing enough in adolescent health. The everyday lives of adolescents are intertwined with technology, and with 95% having access to a smartphone, digital health tools offer a promising opportunity to reshape how youth access healthcare services. However, are Australian digital health initiatives meeting adolescents' needs? The short answer is no. A recent study found that the 21 currently publicly available digital health prevention initiatives for adolescents are limited in scope, focusing mainly on mental wellbeing, leaving gaps in support for nutrition and physical activity, which are known protective factors for mental wellbeing and physical health. Australian federal funding strongly supports culturally targeted health interventions, but digital health initiatives lack specificity for priority population groups. For example, only four digital initiatives were specifically designed for First Nations adolescents. Additionally, available digital health initiatives were rarely co-designed with adolescents, using complex language and found on platforms unlikely to be used by young people, like government websites. The digital world is evolving rapidly, and evidence-based digital health initiatives are falling behind. It is important to view these gaps as an opportunity to intervene and provide benefits for young people today, the adults they become, and the next generation of children they will parent. The bigger problem is that health and wellbeing status are declining globally, with the majority of adults not meeting physical activity or nutrition recommendations, and non-communicable diseases now the leading causes of death. The escalating prevalence of these conditions places psychological and physical burdens on individuals, but also financial, workforce, and healthcare burdens. The Australian federal government's focus on Healthy Ageing aims to improve overall health and wellbeing for Australians aged 65 and over, but 45.6% of adolescents report a diagnosis of at least one non-communicable disease. To successfully promote Healthy Ageing, intervention should begin much earlier than adulthood. Adolescents are part of the solution to healthy ageing. Investment in adolescents has been described as one of the strongest mechanisms available to safeguard the collective future of humanity. The global population of adolescents is the largest in history, with 3.3 million young people aged 15-24 years living in Australia. Promoting good health in adolescents establishes lifelong protective behaviours that prevent the future burden of disease. The National Preventive Health Strategy emphasises preventive health action as the key to achieving a healthier Australia, but the lack of prevention investment in adolescents may limit progress towards achieving strategy targets. Investment goes beyond dollars. In Australia, investment in adolescents is often part of broader health initiatives, yet it could yield potential returns of $10 USD for every $1 USD spent. However, supporting adolescents requires more than financial investment. A study found that adolescents highly valued their involvement in decision-making processes, which improved adolescent health outcomes. Yet, opportunities for adolescents to engage in initiatives that improve their health and wellbeing are rare, going against expert advice from the United Nations, the World Health Organisation, and The Lancet Commission. The Health Advisory Panel for Youth at The University of Sydney (HAPYUS) is a successful example of how utilising the voices of young people is crucial to shaping research. Adolescents should not be passive recipients of initiatives that directly impact their health and wellbeing. Digital technologies are part of an equitable solution. With the technology sector expanding by 80% in five years, the potential of its use to improve health is growing. While digital solutions may present challenges, including accessibility and poor digital literacy, they can be more equitable. At a relatively fixed cost, they can be scaled globally to deliver accessible healthcare. The National Digital Health Strategy (2023-2028) encourages embracing the digital revolution to provide better access to healthcare. Researchers have taken advantage of the digital revolution, using artificial intelligence, social media, and text messaging to deliver preventative health care to adolescents. The Health4Me study, a successful co-designed, text-message health prevention initiative for adolescents, highlighted how adolescents advocate for co-designed digital health solutions. While the digital world is harnessed to improve health, we need to empower adolescents to be involved in initiatives that are for them. Their first-hand experiences ensure that solutions are relevant and effective, preventing a USD $4.1 trillion cost of inaction by 2050. We cannot afford not to invest in adolescents. The authors declare no conflicts of interest. ART is supported by a University of Sydney Postgraduate Research Scholarship in Adolescent Health and Nutrition. SRP is supported by a University of Sydney Horizon Fellowship and a National Heart Foundation Future Leader Fellowship (Award ID: 106646). The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA, or InSight+ unless so stated. Subscribe to the free InSight+ weekly newsletter here. If you would like to submit an article for consideration, send a Word version to mjainsight-editor@ampco.com.au.