In this thesis I explore sunscreen use-practices, imaginaries, and material flows. I aim to understand how young people in the globally-immersed UK use sunscreens and how they makesense of them. Specifically, I follow Donna Haraway’s practice of implosion, employing theconcepts of care and toxicity to explore how sunscreens are employed to protect particularbodily ideals, aspects of embodied subjectivities and material-discursive boundaries. In following these various forms of protection, I ask what normative discourses, ecologies andbodies are, in turn, made vulnerable. The main corpus of my study comes from interviewconversations with eight people. Their stories highlight how sunscreens mediate understandings of skin, places, bodies, and social relations. I analyse sunscreen advertising from 1979to 2019 to investigate harmonies and conflicts between the cultural imaginaries curated bysunscreen companies and the stories which emerged from these interview conversations. Ialso put these materials into conversation with sunscreen discourses from the biological sciences, asking how these cultural works infuse sunscreen practices and material-semiotics.This thesis is an exploratory journey which encounters tanning, ageing, beauty, ‘race’,smells, places, intimacies, sun-burns, skin cancers, bodily boundaries, ‘Endocrine Disruptors’, toxic ecologies, and emplaced knowledges. It traverses disciplinary boundaries, following attitudes from the feminist and environmental post-humanities in bringing togetherapproaches, methods and theorising from many varied fields of scholarship usually locatedin the humanities, social sciences, and ‘natural’ sciences. As such, this thesis is a wide-ranging, thick description of how sunscreens are used in desires for protection and what is contingently and consequently made vulnerable.