Epigenetics designates both a domain of biology and the phenomenon it studies: the modulation of gene expression by factors beyond (epi-) the genome, such as environmental and/or contextual ones. As such it points to the entanglement between biological and socio-environmental determinants of health. The study of these ‘biosocial’ phenomena raises a great deal of interest and scepticism on the side of the social sciences. Is this the life sciences’ turn towards ecological and socially embedded conceptions of biography and biology? Or is it, instead, a new way to reduce complex biosocial conceptions of the human condition to the dynamic of molecules and chemical modifications of DNA? This project addresses precisely these questions at the intersection of Science and Technology Studies (STS) and the situated practices of epigenetic sciences.First, the project consists of an ethnography of the mundane labour scientists perform to produce alternative epigenetic accounts of ‘stress’ as hybrid biological, psychological, behavioural and social phenomenon. Specifically, the project focuses on how epigenetic researchers produce different accounts of the biosociality of ‘stress’ in mental/psychological (e.g. depression, anxiety, schizophrenia) and somatic/metabolic (e.g. obesity, hyperglycaemia) conditions. Second, the project sets up a collaborative research group (Co-LaboRG) on the designs, methods, techniques and objectives that could facilitate the collaboration between biomedicine, social sciences, public health research and policies around epigenetics. This collaborative experimentation aims at identifying – and possibly closing – the conceptual and methodological gaps that currently hinder inter- and trans-disciplinary approaches to epigenetics.