Aim: The aim of the paper is to understand how people who use drugs (PWUD) experience stigma. To examine this issue, this paper draws on Bourdieu's logic of practice to understand how social harm emerges relationally between people via ‘mechanisms of stigma’. Methods: This paper draws on 24 qualitative semi-structured interviews with people who use drugs (heroin, crack/cocaine, amphetamine, ecstasy; 11 men/12 women/1 transgender) living in the northeast of England. Thematic analysis of data was undertaken and coded in Nvivo. Findings: PWUD experienced stigmatisation relationally with family, employers, health workers, Criminal Justice System, and the public for reasons linked to (but not limited to) their drug use, social class position, and their appearance. Stigmatisation shaped how participants saw themselves as a person ‘lacking’ in a valued or worthy identity. Social relations had detrimental effects on mental and physical health, and how participants accessed health services. Conclusions: Models of Social Determinants of Health (SDoH) currently focus almost entirely on a positivist, material ‘reality’ in which a person lives (housing, employment, food insecurity, healthcare, education, access to services), overlooking the ways in which social relations and a practical ‘mastery’ of social space contribute to health and inequalities. Furthermore, relational stigma shapes our experience of a healthy life; as such, stigma should be regarded as a SDoH as it contributes to a widening of health inequalities and unfairly impacts marginalised people in society.