The fashion industry has a materials problem. About 60% of all fabrics are plastic-based synthetics that take up to 200 years to decompose, according to the UN Environment Programme. That's a lot of landfill commitment for a T-shirt you'll wear a handful of times.
Keel Labs, founded by Aleks Gosiewski and Tessa Callaghan while they were students at the Fashion Institute of Technology, started with a simple question: what if we used something that already grows in the ocean, absorbs carbon dioxide like trees do on land, and doesn't require us to invent an entirely new supply chain.
The answer was kelp.
They've developed Kelsun, a fiber made from seaweed that's completely biodegradable, naturally flame-resistant, and — critically — creates zero microplastics. It works in both traditional textiles and non-woven fabrics, which means it can actually slot into existing manufacturing processes rather than requiring fashion brands to completely rebuild their operations.
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Start Your News DetoxThe startup has already partnered with Stella McCartney and Outerknown, with Kelsun now appearing in T-shirts, vests, and other garments hitting the market. McCartney spoke about the shift at COP28: "We need to get creative and innovative with alternatives, moving beyond the limited materials that the industry has been working with traditionally. If we can work collaboratively with these goals, we can actually begin doing business in a way that regenerates our planet instead of only taking from it."
What makes this different from other "sustainable" fabric announcements is the practical foundation. Kelp regenerates quickly, it's already harvested in many parts of the world, and the material performs — it doesn't require consumers to accept lower quality or higher prices as the trade-off for conscience. It's not a perfect solution (nothing is), but it's the kind of concrete alternative that actually changes the math for brands deciding what to make next season.
As more designers experiment with kelp-based fibers, the real test will be whether the cost and scalability can keep pace with demand. But for the first time in a while, the fashion industry has a plastic alternative that doesn't require choosing between sustainability and wearability.
