Urgent sustainability efforts are needed, particularly in resource-intensive industries such as the pharmaceutical sector. Pharmaceuticals (“drugs”) are made up of active pharmaceutical ingredients (APIs) and excipients. Excipients are essential components in drug formulations. They play a significant role for the applicability of drugs. In recent years the environmental impact of APIs received much attention. In contrast, the environmental impacts of excipients most often are not considered. Here, we systematically evaluate the environmental impacts of 38 pharmaceutical excipients through cradle-to-gate life cycle assessments (LCAs) and environmental biodegradability analysis. This integrated approach provides environmental scores for excipients. Our findings identify critical environmental hotspots, particularly in excipient application fields such as binders. This calls for greener, more sustainable alternative excipients. As a key outcome, the “Excipient Selection Guide” is introduced based on a database which provides data for relative ranking to environmental issues. It will enable the pharmaceutical industry to determine whether new or existing alternatives truly represent a more sustainable choice. The data and the method can be used to design novel, greener, and more sustainable excipients of the future (“Benign by Design”). While focused on the application for pharmaceuticals, the guide's principles and data are applicable to other sectors, including food, chemistry, cosmetics, and personal care, supporting sustainability across industries where the same compounds are used.