The Living Lab for Health aims to tackle complex and persistent health challenges by fostering multistakeholder innovation networks. Its core mission is to drive system innovation for increased collective impact. The Lab focuses on issues demanding mutual learning and knowledge integration to design and implement comprehensive, high-leverage interventions. It considers crucial leverage factors across various systemic areas, including social, technological, research and innovation, environmental, economic, political, and institutional aspects. The Living Lab facilitates innovation networks to collaboratively design and implement these interventions, emphasizing mutually reinforcing, decentralized, and collaborative approaches. It adheres to robust methodological frameworks designed to amplify the impact of research and innovation, and it conducts its own research to refine its methods and disseminate its findings. Two primary categories of complex health challenges are addressed: Health protection and promotion, such as healthy and sustainable diets, affective sexual health, mental health, and COVID-19 prevention. Prevention, diagnostic, and therapeutic challenges, especially those that are comorbid or require diverse factor consideration, like Long COVID. Operating as a think tank, the Lab provides a space for strategic reflection, learning, exploration, and the co-creation of transdisciplinary knowledge and interventions, involving a wide range of actors. A key initiative is the co-coordination of the Barcelona CaixaResearch Living Lab, alongside the Barcelona Institute for Global Health (ISGlobal). This initiative, launched by Barcelona City Council and "la Caixa" Foundation, focuses on promoting systemic health innovation in Barcelona, including collaborations with IrsiCaixa and Hospital Germans Trias i Pujol. The Lab targets a diverse array of stakeholders, varying by the specific health challenge (scientific-technical vs. socio-technical).