In dark times of global health polycrises, which are marked by pandemics, widening health inequalities, deteriorating mental health, climate breakdown, and the erosion of public care systems, psychology cannot and does not only serve as a tool to describe the human condition. Instead, it increasingly operates as a political force that shapes how health, suffering, and care are named, governed, and internalised; in short, how we become and remain (un)healthy. This paper argues that contemporary conceptualisation of health, particularly in late capitalism, cannot be understood as a neutral biological or psychological state, but must be conceptualised as a psychologically mediated and politically situated process through which individuals learn to interpret, regulate, and moralise their bodily and emotional experiences. The paper begins by defining health as a mediated psychological function, drawing on sociocultural psychology. From this perspective, health does not exist as an immediate or self-evident property of the body or mind. Instead, it emerges through processes of mediation, whereby individuals learn to recognise sensations, emotions, and states of being through culturally available signs, narratives, and institutional practices. Experiences such as pain, fatigue, anxiety, or vitality become meaningful only insofar as they are interpreted through language, diagnostic categories, educational norms, and everyday routines that teach individuals what these experiences signify and how they should be managed. As such, health functions as a higher psychological process, not a state discovered within the body itself, but a learned mode of interpretation and self-regulation that is acquired through participation in cultural practices. Building on this, the paper further draws on critical Marxist theory, postulating that these processes are not neutral, and examining why particular meanings become dominant, whose interests they serve, and how they are embedded in relations of power. To do so, the paper identifies four dominant psychological discourses through which health is produced and stabilised: health as personal responsibility, health as productivity, health as medical mandate, and health as consumerism. These discourses circulate across institutions such as schools, healthcare systems, workplaces, and digital platforms, functioning as cultural tools that organise both meaning and conduct. Through psychological mechanisms of mediation and internalisation, these discourses then shape subjectivity by translating structural pressures into individualised projects of self-management, self-regulation, resilience, and optimisation; they also link health to moral worth, e.g., being healthy becomes evidence of discipline, responsibility, and functionality. At the same time, illness or distress are implicitly coded as failures of self-management. Although these discourses often appear empowering, critical analysis reveals that they systematically shift attention away from structural, cultural, historical, and economic conditions and power relations. Dominant psychological theories and approaches also inadvertently reinforce these dynamics, particularly those grounded in individualistic models of health, rational decision-making, and behaviour choice and change. Through privileging those theories, research and practices, psychology contributes to the reproduction of widening health inequalities. The paper calls for the denaturalising of psychological concepts of health and well-being; however, it does not reject psychological knowledge or therapeutic practice, but instead asks that they be situated within the social relations that shape their meaning and use. To do so, it is critical to understand health as a relational and dialogical process rather than an individual experience; by doing so, a space for an alternative psychological theory of health grounded in solidarity, interdependence, and collective care could be opened.