Seaweed Hits High Street in H&M and Keel Labs Venture

H&M is bringing seaweed fashion to the high street through a new collaboration with Keel Labs. 

The result is a summer line manufactured with Kelsun, a textile fibre made from algae. 

With environmental impact high on the agenda, this partnership explores how marine materials can reshape sustainable fashion manufacturing.

The new material, Kelsun, is a seaweed-derived fibre created by Keel Labs. Seaweed, or macroalgae, is a regenerative marine organism that absorbs carbon dioxide from oceans in the same way trees remove it from the atmosphere. 

Once harvested, the algae are combined with a bio-based carrier to produce a fabric suitable for non-woven textiles. The resulting material is non-toxic, contains no microplastics and decomposes naturally at the end of its life.

This innovation has already found a place in H&M’s sister brand, & Other Stories, and now reaches a wider audience through H&M’s global reach. The launch follows Kelsun’s first commercial outing in 2024 through a limited collaboration with designer Stella McCartney.

Manufacturing materials from marine organisms

Keel Labs is led by Co-Founder and CEO Aleks Gosiewski, who started developing Kelsun in 2017 while still a design student. 

The project began as a response to the fashion industry’s high levels of textile waste. The idea was to create alternatives that match the performance and aesthetic of existing materials but reduce their environmental cost.

“Being named Forbes 30 Under 30 introduced me to a network of young entrepreneurs who share the same mission,” says Aleks. “At the end of the day, our goal is simple: we want to create materials that allow fashion brands to meet their sustainability goals without compromising on quality or performance.”

The Kelsun production process is rooted in low-impact design. Seaweed does not require fertilisers or pesticides to grow and does not take up agricultural land. Unlike synthetic fabrics, Kelsun breaks down naturally, and when used without blending, it remains recyclable. However, mixing it with other fibres can create issues for end-of-life processing.

Despite its environmental benefits, manufacturing Kelsun at commercial scale remains expensive. This limits its availability and presents a barrier to wider use across more fashion lines.

It also complicates efforts to streamline recycling processes if blended with other textiles. But Keel Labs is moving forward, aiming to grow the supply chain to meet increasing demand.

“It all started with seaweed and now Kelsun is on shelves around the globe through our launch with & Other Stories, made possible by the visionary team there and at H&M Group,” says Aleks. “To our team at Keel Labs, thank you for your dedication, creativity and hard work to build a better future!”

How H&M aims to meet climate targets

Cecelia McNeil, Sustainability Manager at H&M, describes the launch as part of the company’s ongoing search for new techniques and materials. 

“We continuously seek new technologies and materials to evolve our designs. For us, fashion and innovation are intertwined,” explains Cecelia.

The new summer range uses the fibre in its undyed state, highlighting its natural tones and texture. 

“Wear the pieces as a set or style casually as summer separates, they are soft, relaxed and kind,” says Cecelia. “Using the natural colour of the fibre also felt essential, no dying techniques were used – the set is presented in its purity.”

H&M has set multiple environmental targets, including sourcing 30% of its materials from certified recycled content by the end of 2025. 

By 2030, the company hopes to see 100% of its materials either recycled or sustainably sourced, using 2019 as a baseline.

The company also targets a 56% cut in Scope 1, 2 and 3 greenhouse gas emissions by 2030, and wants full compliance with the ZDHC (Zero Discharge of Hazardous Chemicals) Manufacturing Restricted Substances list across all tier one and two production facilities.

Other eco-friendly materials already in use at H&M include regenerative wool from NATIVA and recycled silver sourced through urban mining. These are used alongside Kelsun as part of a wider strategy to reduce the fashion group’s environmental footprint.

Seaweed’s role in fashion’s future

Using marine-based fibres could lower fashion’s reliance on water-intensive crops and petroleum-based synthetics. 

Seaweed does not need irrigation or chemical treatments and contributes to carbon sequestration – where CO2 is absorbed and stored in the ocean.

Yet despite its potential, scaling production and cutting manufacturing costs remain hurdles for wide adoption. 

For now, H&M’s move with Keel Labs signals a step toward greater use of bio-based textiles on the high street.

“We urgently need climate-positive change, and we need it now – but we’re in it together,” says Aleks.