Abstract Background Sustainable living plays a crucial role in creating a fairer society, but various constraints prevent consumers from adopting sustainable behaviours. This study investigated the reasons for non-adoption of sustainable products or behaviours among the Italian population. Methods From January to June 2023, we surveyed the Italian population using a 40-question online survey that asked about knowledge, awareness, and attitudes toward sustainable behaviours and products. Participants were asked about the reasons why they did not engage in a certain behaviour or did not use a selected product. Descriptive statistics, t-test and chi-square tests were performed to assess association with participant characteristics. Results The 420 participants had a median age of 39 years (interquartile range: 32-56), 66% were female. The largest discrepancy between knowledge of sustainability impacts and implementation was in the personal care (92% knowledge, 31% implementation) and transportation (85% knowledge, 48% implementation) domains. In general, the main reasons for not using the surveyed products were practical complications in everyday life (25%), the difficulty of finding or producing them (23%) and their cost (13%). Specifically, practical complications (42%) were the main reason for not adopting sustainable behaviours in the transport domain. In the personal care domain, low confidence in product quality or ignorance of their existence accounted for only 26% of reasons for non-use, while supply problems, practical complications in everyday life and existence unawareness accounted for 61%. Conclusions Targeted measures are needed to address the reasons for non-use or adoption of sustainable products and behaviours. In this way, these actions will help to promote healthy living, protect our planet, support socio-economic development, and ensure global prosperity. Key messages • A greater sustainability- implementation awareness gap was found in personal care and transportation domains. • The main reasons for not implementing sustainable living were practical complications in daily life, supply difficulties and product cost.