###### Abstract  
Sustainable product design uses methodologies focused on eco-effectiveness and eco-efficiency for the proposal of innovative technological solutions and for the control of environmental impacts during the product life cycle. One of the main drawbacks of such techniques is their qualitative nature, associated with a decision-making process that is sometimes arbitrary, or with unverifiable data; this means that several complementary tools are currently being used to reduce the error in the results obtained. This situation makes the unification of procedures necessary. In this context, this research develops a methodology for the sustainable design of industrial products that integrates life cycle assessment (in its environmental, economic and social application) and cradle-to-cradle techniques. For this purpose, a new assessment process is proposed, based on damage, developing LCA+C2C endpoint indicators. The methodology is subsequently verified in a case study of products for sustainable mobility (city trike electric). The results show that an integrated LCA+C2C assessment can help to propose more balanced sustainable strategies and would be a suitable method to measure tradeoffs between economic, social and environmental results, for practical purposes and future redesign. The unified method provides a procedure to design a solution with a trade-off between eco-efficient and eco-effective criteria; it also simplifies the design phases, facilitates the interpretation of the results and provides a quantitative scope to the cradle-to-cradle framework. title= [1][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]  
value with minimum resource use and minimum pollution [4]. Methods of impact analysis [5; 6; 7] utilize different formats: checklists, experts' judgement, flowcharts, multi-criteria analysis or simulation models. As examples, the following stand out: cumulative environmental impacts [8], life cycle assessment (LCA) [7; 9], eco-costs [10], material and substance flow analysis [11], environmental and material flow cost accounting [12] and environmental risk assessment [13]. The evaluation identifies those activities and processes in the product life cycle that generate the greatest environmental load; then, a prioritization of actions is established through the control of polluting substances in two phases: (1) reduction of midpoint impacts (changes in natural environmental aspects, such as global warming or acidification) and (2) reduction of endpoints (damage effects on ecosphere elements: human being, ecosystem and resources). This model is the most widely used at present; it is operational and allows economically and technically viable solutions. However, it offers short-term solutions that do not eliminate the problem. Furthermore, the strategy of minimizing impacts does not promote the proposal of cleaner alternatives; in other words, the solutions manage to reduce the consumption of resources and energy, emissions or waste, but do not reach zero impact. On the other hand, eco-effective solutions [14; 15; 16; 17] are proposed from the perspectives of damage restoration, removal and repair actions, closure of cycles and dematerialization [3; 5; 18; 19; 20]. Eco-effectiveness is a proactive approach that proposes the identification of the processes with negative impacts, to replace them with new solutions; it identifies the causes of the problem in order to eradicate it completely. It uses strategies supported by eco-innovation: clean alternative solutions, balanced in the social, economic and environmental dimensions, which also generate zero impact or even a positive impact (damage restoration). The tools associated with this approach are more limited. In general, these are conceptual design guides and strategy proposals; if any assessment tool is included, these are usually qualitative or semi-quantitative.