The present study draws on the concepts of motives and heuristics to thoroughly understand consumers’ sustainable consumption behaviour in the context of personal care products. The mixed-methods approach combines real purchasing data with in-depth qualitative data to generate insights with a high external validity. In the first section of the study, quantitative analysis is applied to actual purchasing behaviour (n = 10,772,477) to identify market trends. Three main groupings, along with specific heuristic cues, are established. In the second step, a qualitative study (n = 21) provides deeper insights into consumers’ motives and decision-making processes. By synthesising the quantitative and qualitative research findings, a segmentation approach is developed. Relevant motives and values, and corresponding specific heuristic cues are identified for each consumer segment. Analysis suggests that consumers are motivated by self-interest and environmental motives, and that they use simple heuristic cues to make quick and satisfying purchasing decisions. Both retailers and manufacturers can leverage these insights to seize the opportunities of the developing market for sustainable personal care products.