Purpose: The aim was this study was to test the effectiveness of the Mexican User Satisfaction Index of Circular and Social Economy (MUSI-CSE) methodology to improve user acceptance and the adoption of biodiesel from the Cowichan Bio-Diesel Co-op (CB-DC), a social enterprise that upcycles cooking oil waste. Approach: The external strategy is to study factors of user experience with products and/or services and internal processes. This type of economy tends to build its value chain independently to avoid barriers in the economic structure. Methodology/Techniques: MUSI-CSE presents a model of satisfaction (present acceptance) and loyalty (future acceptance) factors and a measurement system comprising the same factors. It also identifies and monitors interventions in key factors and evaluates their effectiveness. Here, MUSI-CSE has been tested through a longitudinal and prospective study. In-depth interviews, surveys, SEM, and PLS were used. Findings/originality/applicability: User acceptance and adoption are based on self-benefits and the achievement of specific sustainable local development goals. Satisfaction did not change. Loyalty did experience a statistically significant increase at a 95% confidence level, and sales increased by 26%. It can be concluded that MUSI-CSE innovation contributed to improving users’ future acceptance and adoption. In the future, MUSI-CSE will be adjusted based on other case studies and will support the co-creation of an international methodology and index of circular and social economy.