This paper will explore themes of relaxation, letting be, and letting go in the work of the contemporary French philosopher Catherine Malabou. Writing at the intersections of philosophy, neuroscience, and other diverse disciplines, the concept at the core of Malabou’s work is that of plasticity: the ways in which the body and brain are ‘plastic’, and thus radically mutable and transformable. Malabou’s work is concerned with the question of how we might activate or embrace this plasticity for socio-political change and emancipation. One of responses to this ‘how’, I will argue, is to do precisely with modes of relaxation, letting be, and letting go that are more or less latent in Malabou’s elaboration of plasticity. These modes of relaxation and release are not to be confused with ideas of rest, R&R, stress-relief, wellness, etc.; rather, I argue, they invoke or induce a radical state of self-abandonment or self-shattering (of the body, brain, spirit) at play in Malabou’s accounts of profound transformation and metamorphosis. In his book La Soltura del cuerpo (2018), Cristóbal Durán analyses what he refers to as ‘la soltura’ in Malabou’s account of the plastic body and brain, which might translate from the Spanish as ‘ease’, ‘release’, ‘setting free’, but also ‘skill’. Durán here draws upon instances where Malabou describes plasticity through a lexis of release or letting go. Meanwhile, Malabou herself writes a preface to Anne Dufourmantelle’s Puissance de la douceur (2013), in which she praises the radical potentiality of Durfourmantelle’s concept of douceur, softness or gentleness. This gentleness, Malabou stresses, is not the kind of relaxation we find in neo-liberal approaches to meditation, mindfulness, yoga, etc., but an altogether more fundamental and radical instance of letting go. Bringing together these ideas from Malabou, Durán, and Dufourmantelle, I want to extend these theorisations of relaxation across three other interlocutors: the French Buddhist monk Matthieu Ricard (Cerveau et Méditation, 2017), who brings philosophy, meditation, and neuroscience together; the architects and philosophers Shusaku Arakawa and Madeline Gins, who design built environments which relax and transform the body; and experimentations with psychedelics in the pursuit of neural and socio-political transformation in the movement known as ‘acid communism’. I ask: what technologies and practices (medical, architectural, spiritual, etc.) might induce the kinds of relaxation present in Malabou’s philosophy? What practical implications and potentials would these states have for the body and mind? And what forms of socio-political transformation might these states of relaxation bring about?