Fy™ by Hydefy: Fungi-based, vegan alternative to leather
Hydefy’s mycelium-based Fy™ made its fashion industry debut at the Stella McCartney Summer 2025 runway show. Taking the shape of our newest vegan icon, the Ryder bag in a metallic silver, the scalable, responsible material uses fungi and sugarcane-derived inputs.
Who are Hydefy?
Hydefy is a responsible, animal-free materials innovator crafting new high-performance textiles using fungi originating from Yellowstone National Park’s volcanic hot springs, first discovered through NASA-funded research.
What is Fy™?
Using a proprietary fermentation technology, Hydefy grows Fy™ – a new-to-world mycelium-based material. This is then combined with sugarcane waste-derived inputs to create a durable, versatile textile that is entirely vegan, cruelty-free and planet-friendly.
Why is Hydefy better for the planet than other leather alternatives?
Through innovative fermentation technology and scalable downstream processes, Hydefy significantly reduces resource consumption, greenhouse gas (GHG) emissions and pollution compared to existing leather alternatives.
What makes Hydefy better for the planet than other fungi-based alternatives?
Even when compared to other fungi-based technologies, which can take a couple of weeks to grow, the Fy™ used to create Hydefy grows in less than 3 days. Moreover, Hydefy partners with suppliers holding Bonsucro certification for sugarcane inputs and uses carbon-negative inputs where available to ensure biodiversity conservation.
Why is leather bad for the environment?
Multiple studies have shown that vegan alternatives can have less than half the carbon footprint of leather, which kills over 1 billion creatures annually (PETA) and is driving the destruction of key ecosystems like the Amazon (WWF) – with animal agriculture and cattle farming driving 80% of deforested areas. There is a human cost as well, with 90% of Bangladeshi tannery workers dying before the age of 50 (The Guardian).
Stella McCartney is constantly exploring plant-based, regenerative alternatives that do not harm animals and heal Mother Earth. Harmonious to this philosophy, the innovators behind Hydefy prioritise practices and inputs that focus on revitalising material sources, systems and communities.
The Summer 2025 collection will be available from February 2025 at Stella McCartney boutiques worldwide, stellamccartney.com and selected retailers globally.
*Source: 2023 Frontiers Special Issue released by the United Nations Environment Programme
