The Next Stride: Bio-based Materials for Footwear Soles
“The Next Stride: Bio-based Materials for Footwear Soles” aims to validate the performance and environmental impact of bio-based polymers as sustainable alternatives to the fossil fuel-derived materials currently used in footwear soles. The objective is to collectively de-risk the transition to these “next-generation” materials by rigorously testing their technical properties and assessing environmental benefits. Ultimately, the purpose is to accelerate the adoption of these bio-based solutions and pave the way for a more sustainable footwear industry.
What’s the challenge?
The global footwear industry, a $400 billion market in 2023 projected to reach over $550 billion by 2030, while offering considerable economic opportunities, simultaneously underscores the escalating environmental impact associated with footwear production, consumption, and disposal. The core problem this project addresses is the industry’s heavy dependence on fossil fuel-derived polymers like PU, TPU, EVA, and Rubber for footwear soles, which has dire consequences for the planet. The carbon footprint of a typical pair of synthetic running shoes is estimated at 14 kg of CO2 equivalent, with an overwhelming 97% of this impact directly attributable to the raw material processing (29%) and manufacturing (68%) stages. This highlights that the choice and production of materials are critical factors in the footwear industry’s environmental footprint.
Executive Summary
The Next Stride: Bio-based Materials for Footwear Soles is a 12-month project led by Fashion for Good, with participation from brands adidas, Target, and Zalando. The initiative aims to address the footwear industry’s heavy reliance on fossil-fuel-based polymers by validating bio-based material alternatives. The project’s core objectives are to benchmark the performance of these new materials against conventional options, conduct comprehensive life cycle assessments to understand their environmental impact, and explore cost optimisation to overcome the price premium that currently hinders widespread adoption.
This initiative represents a critical first step in determining whether bio-based, potentially biodegradable materials offer a genuinely viable alternative to both traditional fossil-fuel materials and current recyclability-focused approaches. The findings from this work can then be used to inform the development of a roadmap for larger-scale adoption, incorporating considerations such as impact accounting, feedstock availability, end-of-use solutions, and the infrastructure needed to support broader implementation.
Goals of the Project
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To develop an understanding of the environmental impact of bio-based materials through comprehensive Life Cycle Assessments (LCAs), and to clarify how biogenic carbon is treated under various established methodologies and standards.
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To assess and benchmark bio-based polymers and polymer blends against conventional fossil-fuel-derived EVA, PU, TPU, rubber, and TPR. This will validate their potential as a material for footwear soles, with a focus on performance and impact characteristics.
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To explore cost optimisation opportunities for mitigating the existing price premium associated with bio-based footwear materials, which limits brand adoption and delays the market signals needed to justify large-scale investments.
Innovators
Innovation Partners
Relevant Resources
What are biomaterials in fashion?
Understanding Bio-Material Innovations: A Primer for the Fashion Industry
The fashion industry is undergoing a materials revolution, with bio-based innovations at the forefront of sustainability efforts. This report, developed by Biofabricate and Fashion for Good, provides a foundational understanding of bio-material innovations, their definitions, processes, and potential for large-scale adoption. With contributions from leading innovators, brands, and manufacturers, this primer aims to drive informed decision-making and enhance cross-sector collaboration.
Fashion for Good launches the Feedstock Assessment for Biosynthetic Innovation
Closing the Footwear Loop
The “Closing the Footwear Loop” project is a major initiative led by Fashion for Good, bringing together 14 leading fashion and footwear brands and their existing circularity programs to tackle the complex challenges of circularity in the footwear industry. The project aims to transform the current linear “take-make-dispose” model into a circular one.
Fast Feet Grinded Collaborative Pilot
The aim of the pilot was to test and validate the FastFeetGrinded footwear recycling process by evaluating the quality of outputs and understanding the environmental impacts of the process. FastFeetGrinded is a company specialising in footwear recycling that accepts all types of footwear as feedstock to produce sorted material granulates with zero waste streams. FastFeetGrinded aims to deconstruct any type of pre- and post-consumer shoe, separating footwear into substituent components, which are then subsequently grinded down and processed to create material streams for repurposed use.
Other Projects
Sorting for Circularity Rewear
Fashion for Good expanded its Sorting for Circularity framework to address the challenge of sorting for rewearable textiles to understand better their resale potential and the demand across the second-hand market. We launched an 18-month initiative in January 2024 in collaboration with Circle Economy, brand partners adidas, Inditex, Levi Strauss & Co. and Zalando to enhance the sorting of rewearable textiles using innovative AI technologies. The project seeks to improve garment recovery for resale, promoting circularity in the fashion industry.
Behind the Break
Behind the Break is a multi-phase research initiative developed by Fashion for Good in collaboration with The Microfibre Consortium. The project takes a research-led approach to advance the fashion industry’s understanding of fibre fragmentation, addressing uncertainties in existing testing protocols and key knowledge gaps. By supporting the development of a more credible and consistent foundation, the initiative aims to enable stakeholders to make informed decisions and take decisive action to mitigate fibre fragment pollution, while leveraging the best available science.
Behind the Break 2.0
Behind the Break 2.0 is a targeted research initiative focused on addressing fibre fragmentation in textiles, building directly on the work started in Phase 1.0 (2024–2025), which tested the strengths and limitations of different methods used to measure fibre loss, identifying how much results vary between labs, and exploring what drives fibre shedding across three fabric types: cotton knit, cotton woven, and polyester knit. Phase 2.0 seeks to increase confidence in data quality, consolidate and refine existing testing approaches and knowledge across selected fabric archetypes, and deepen supplier engagement to support wider data collection within the space.
