In this talk, I present the first reflections of an ongoing research project dedicated to investigating the processes of elaboration of gendered bodies among the Tupi peoples of the sixteenth century. By tracing the vocabulary of substances abundantly present in the chroniclers’ accounts—references to blood, semen, cauim, puba, among others—I seek to evoke echoes of a cosmopolitics of substances, in which gendered bodies were formed by voluntary, collective, and densely conceptualized acts. In this first approach, I propose a panoramic view: I begin with the role of substances and their flows in the rituals of post-menarche and post-homicide seclusion, which aimed at the formation of adult male and female bodies, and I conclude with a reflection on some figures that escaped the binary colonial technology of genders used by the chroniclers: the transgender figures “tebira” and “çacoaimbeguira,” the young “panema” and the old “uainuy.”