This book is about gym culture, the pursuit of fit, muscular bodies and the use of drugs as a means to get there. Building on the international research literature and in-depth interviews with men who have experience of image and performance enhancing drugs (IPEDs), the book explores the fascination with muscles, motivations for using drugs to enhance them, assessments of risks, and experience of side effects. The book examines what the altered body does to the men’s identity, self-image and relationships with peers and partners. Taking an evolutionary psychological approach, it also investigates the biological and psychological foundations of the fascination with the muscular body and discusses the notion of precarious manhood. Building on these analyses the book considers the political and regulatory initiatives in place to prevent the use of IPEDs and assesses those strategies’ potential to reach their aims. This is essential reading for anybody with an interest in the issue of drugs in sport, the ethics of sport, sociology of sport, sociology of the body, masculinity or public health.