Spiber’s Brewed Protein™ fiber was featured in British fashion brand Stella McCartney’s Winter 2026 collection, unveiled at Paris Fashion Week.

Spiber and Stella McCartney have spent more than four years developing materials together and exploring new possibilities for creating the ideal expression for the collection. Stella McCartney has long challenged the conventional notion that luxury must depend on animal-derived materials. This collaboration goes beyond simply introducing a new material; it represents an effort to expand the very definition of luxury.

Much of the fashion industry’s environmental impact originates from raw materials. To fundamentally reduce this impact, it is necessary to rethink not only how products are designed, but also how the materials themselves are produced. Spiber’s Brewed Protein™ fiber makes it possible to produce protein-based materials through fermentation rather than livestock farming. Moving from ranching to precision fermentation represents a structural transformation in the way materials are produced.

The collection features exceptionally fine Brewed Protein™ fibers with a fiber diameter of 12–14 microns, contributing to their distinctive texture and smooth, refined hand feel.

Items featuring Brewed Protein™ fiber are scheduled to launch as part of the Stella McCartney Winter 2026 collection. The official launch date will be announced at a later time.

Going forward, Spiber will continue to work alongside Stella McCartney as a partner in advancing new possibilities for fashion through next-generation materials, pursuing a balance between creativity and more responsible manufacturing.