Sustainability has been recognized as a major concern globally since the Brudtland Report, in 1987, and further reinforced in 2015 by the United Nations Sustainable Development Goals (UNSDG) 2030. This paper reviews the methodologies and criteria of sustainability applied to fashion products, regarding products’ environmental footprint (environmental life cycle assessment/analysis; e-LCA), the social issues (including the social life cycle assessment/analysis; s-LCA) and the transparency in reporting sustainability. In our review we seek KPIs (key performance indicators) that allow classification of a pair of shoes or a piece of cloth on a scale from A to E, i.e., products can be compared with a benchmark and classified accordingly with a simple labelling scheme, which is easily understandable by the consumers. This approach is similar to those used to classify electrical appliances, housing energy consumption for thermal comfort, food Nutri-Scores, CO₂ levels of road vehicles, and tire performance. In this review we aim to identify the initiatives and measures being put into practice by the top global fashion brands. We found that, despite the existence of GRI (global sustainability reporting initiative) standard reporting, most companies follow their own methods or others created within the industry rather than those created in the scientific community. Examples include the Higg index, the Transparency Index, and the Social Codes of Conduct (CoC). In this study, we conducted an extensive review of certification schemes and labels already applied to fashion products, and identified a multitude of labels and lack of harmonization in communicating sustainability. As result, we compiled a summary table of all criteria, methodologies, and possible KPIs that can be considered the basis for a benchmark and score of a fashion product. This topic is crucial to avoid “green washing” and a lack of transparency for the buyer’s community, i.e., business to consumer (B2C), and for the business community, i.e., business to business (B2B) relationships, which comprise a complex multi-layer supply chain of suppliers and sub-suppliers. The UNSDG 2030 “Responsible Consumption and Production” frames these efforts to facilitate standardization of KPIs in terms of structure, criteria, and their measurement. The most common KPI is environmental global warming impact (expressed as CO_2eq) based on life cycle assessment/analysis (LCA) principles (established in 2000), which provide an appropriate base to monitor and benchmark products. However, in our innovative review of t-shirt e-LCA, we identified a wide range of e-LCA assumptions, relating to different boundaries, allocations, functional units, and impact categories, which represent a major challenge in benchmarking.

Promoting sustainable consumer behavior is now an obligation under new European legislation, requiring life cycle assessment (LCA) for accurate environmental impact evaluation. Portugal is a key textile producer with an edge in competitiveness in sustainable textile production, driven by electricity-reduced carbon footprints and closed-loop manufacturing. Additionally, while simple spreadsheets can estimate a product’s carbon footprint, openLCA v1.11.0 software, combined with the ecoinvent database, greatly enhances environmental footprint calculations by integrating diverse impact categories that are otherwise difficult to estimate. In this study, openLCA is used to evaluate the environmental footprint of a white T-shirt made in Portugal with 50% recycled cotton from post-industrial wastes combined with 50% organic cotton from Turkey to assist in the design of environmental key performance indicators (KPI). The RECIPE and EF methods (adapted) are used to calculate the environmental impacts and allow aggregation into a single score. The KPI related to the global warming impact is validated using a spreadsheet calculator. We propose an “Envi-Score” based on an A-to-E classification for benchmarking and better communication with the buyers. E is set as the normalized environmental impact of the European benchmark for a mixture of material T-shirts encompassing cradle-to-gate boundaries. The introduction of recycled cotton produced in Portugal proves to be environmentally beneficial over organic and conventional cotton. Organic cotton proves to be beneficial in comparison with conventional cotton for most environmental categories, except for the ones affected by the lower production yield, for example, land use. The hotspots for the main impact categories are identified, and finally, a labeling scheme is proposed to clearly inform about the environmental performance of the products and avoid greenwashing with the “Envi-Score” rate, carbon footprint, land use, and water depletion.

Consumers are increasingly willing to choose more sustainable products, driven by affordability and sustainability considerations. However, they often face difficulties in understanding the multitude of product certifications and identifying “greenwashing” marketing claims. This highlights the need for a clear and harmonized sustainability scoring system that allows consumers to benchmark products. Sustainability encompasses three key pillars: environmental, social, and economic. Accurately scoring a product’s sustainability requires addressing a wide range of criteria within these pillars, introducing significant complexity. This study proposes a multicriteria methodology for scoring the sustainability of apparel products into an A to E label. The approach combines a life cycle assessment covering environmental impacts from “farm-to-gate”, with a social evaluation based on country-level social key performance indicators (KPIs) and factory-specific data aligned with the International Labour Organization (ILO). Additionally, the sustainability score incorporates the impact of product durability, as longer-lasting products can reduce environmental footprint and costs for consumers. The methodology is defined and validated through a case study of a white T-shirt produced with 50% recycled cotton and 50% organic cotton. The results demonstrate the comprehensive assessment of the T-shirt’s environmental and social impacts, providing a detailed sustainability score, highlighting the role of recyclability. This comprehensive sustainability scoring system aims to provide consumers with a clear, harmonized, and reliable assessment of product sustainability, empowering everyone to make informed purchasing decisions aligned with their values. It will also enable brands and retailers to calculate the sustainability score of their products, including in the scope of digital product passport, provided they can ensure traceability and transparency along the supply chain.

Promoting sustainable consumer behavior is now an obligation under new European legislation, requiring Life Cycle Assessment (LCA) for accurate environmental impact evaluation. Portugal is a key textile producer, edge in competitiveness in sustainable textile production, driven by electricity-reduced carbon footprint and closed-loop manufacturing. Additionally, while simple spreadsheets can estimate a product's carbon footprint, openLCA software, combined with ecoinvent database, greatly enhances environmental footprint calculations by integrating diverse impact categories, otherwise difficult to estimate. In this study, openLCA is used to evaluate the environmental footprint of a white T-shirt made in Portugal, with 50% recycled cotton from post-industrial wastes combined with 50% organic cotton from Turkey, to assist the design of environmental key performance indicators (KPI). The RECIPE and EF method (adapted) are used to calculate the environmental impacts and allow aggregation in a single score. The KPI related to the global warming impact is validated using a spreadsheet calculator. We propose an “Envi-Score” based on an A to E classification for benchmarking and better communication with the buyers. E is set as the normalized environmental impact of the European benchmark for a mixture material T-shirt encompassing cradle-to-gate boundaries. The introduction of recycled cotton proves to be environmentally beneficial over organic and conventional cotton. Organic cotton proves to be beneficial in comparison with conventional cotton for most environmental categories, except to the ones affected by the lower production yield, for example Land Use. The hotspots for the main impact categories are identified and finally proposed a labelling scheme, to clearly inform about the environmental performance of the products and avoid greenwashing, with the “Envi-Score” rate, carbon footprint, land use and water depletion.