Changing the tide with seaweed fabric: Introducing Kelsun™️ 

Stella McCartney is a globally recognised leader in conscious luxury fashion. In order to continue pioneering sustainable innovations, our portfolio of planet-friendly, high-quality materials must be ever-evolving.   

The most recent addition is seaweed fabric – a kelp-based yarn, Kelsun™️, produced by Keel Labs and introduced at our Summer 2024 runway show. Keel Labs also is supported by S🌍S Fund, a $200 million investment fund empowering the next generation of innovators, co-founded by Stella McCartney. 

What is seaweed fabric?  

Seaweed fabric, or Kelsun™, is a bio-based material similar to yarn in texture, with a significantly lower environmental footprint than conventional fibres. The manufacturers of Kelsun™, Keel Labs, use an abundant biopolymer found in seaweed to create our luxury and environmentally friendly fibre.   

How is seaweed made into fabric?  

The collected seaweed goes through an extraction process that isolates the biopolymer, which is then combined with proprietary additives and water to form a solution. Next, polymer chains link up to form thousands of fine filaments which are stretched, rinsed and applied with finish before being dried and spun into spools of our Kelsun™.   

Why is seaweed a sustainable material?  

Up to 500,000 tonnes of microplastics from textiles enter global marine environments annually, harming people, animals and ecosystems. Conventional cotton production uses 2.5% of the world’s arable land, but accounts for 16% of all pesticide use – these toxic chemicals put farmers’ health at risk.  

Just as trees do on land, kelp absorbs carbon dioxide in the ocean to survive – this means seaweed is one of the most regenerative organisms on our planet. It exists by harnessing the renewable power of our ocean’s resources alone. Keel Labs’ process of harvesting seaweed is grounded in the use and creation of clean, non-toxic inputs and outputs, meaning their footprint is minimised while the positive impact on our planet is maximised. 


Using 100% less pesticides and 70x less water, Kelsun™️ makes a valid case for a cotton alternative. Highly compostable, the process taking just 61 days in total, it also improves the health of our ecosystems and leverages seaweed as a raw material. 

Where can you find seaweed fabric in the Summer 2024 collection? 

Though Kelsun™ is not commercially viable yet, you can spot some pieces hand crocheted using it on our Summer 2024 runway. We included these garments to illustrate the wealth of next-generation materials out there, and to raise awareness on a larger scale. These two intricately crocheted Kelsun™ garments are dotted with glinting platinum mirrors, loose threads flowing as the models pass, the ecru colour melting into the bare skin beneath. 

Each piece serves as a strikingly breath-taking example of what our industry can achieve in an environmentally friendly, planet-kind way, as does Kelsun™.