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Textiles: a viable market for seaweeds?

Clothes enabled our naked species to conquer the world. In the process of dressing ourselves, we remade the planet. We bred sheep to grow their fur continuously instead of shedding their coat once a year. Silk spurred the first East-West trade and cotton drove industrialization, global capitalism and colonization. Computers were built on the language of looms and to this day, our digital world is replete with weaving metaphors

An expedient market for seaweeds, then?

Seaweed textile 1.0

Back in 2005, German company Smartfiber came up with SeaCell, a yarn mixing lyocell (from wood cellulose) with Ascophyllum nodosum powder. Made in a closed-loop process where no chemicals are released as waste, and claimed to be 100% biodegradable and compostable, it is definitely a step up from fast fashion’s polyester. 

However, there has been controversy, particularly about the amount of seaweed actually included in the yarn. Smartfiber’s website states in bold that it’s 19%, but in the brochure we read that this is the percentage by volume. By weight it’s 4%.

This led some to call into question the positive effects on skin diseases touted by SeaCell and brands using the yarn, particularly since Seacell is woven in with another fabric, usually at around 25% inclusion rate. At this ratio, there is only 1% Ascophyllum in the final product. 

In 2007, a New York Times investigation tested the SeaCell used in Lululemon products and found no evidence that supported any medicinal claims. In fact, the Times’ test didn’t find any elements associated with Asco at all. 

Can textiles incorporating seaweeds have anti-bacterial or anti-inflammatory effects on the skin? It’s certainly possible. For now, however, there really isn’t enough scientific evidence to decide one way or the other, and at which inclusion rate that magic would start to happen.

Lululemon continues to carry the fabric, but all medicinal claims are gone from its marketing and website. Instead, the brand focuses on the breathability and comfort of the material. Good for them. It’s still much more sustainable than average, and customers love its feel. 

But other companies like Savanna Morrow and Alexander Clementine continue to overstate the amount of seaweed in the final fabric. Pyratex even says it’s carbon neutral.

Greenwashing truly is fashion’s original sin.

Seaweed textile 2.0

Alginate wound dressings have been in use since the 1980s. And of course alginate has for a long time played an important role in textile printing, as a thickener for liquid fabric dyes. A new group of startups is now looking beyond these early use cases, to turn alginate into yarn and non-woven fabrics. 

Keel Labs uses a wet-spinning process to create long filament fibers from alginate that are then cut into short staple fibers. From there, the fibers are spun into a yarn called Kelsun. Keel Labs has produced textiles containing 70% Kelsun. 

Karma Beach Club is also using an alginate-spinning process developed at the University of Qingdao. Its t-shirts and underwear contain 15% alginate. Vyld is rolling out its first batch of test tampons, made mostly from alginate. The Horizon project Herewear is looking at seaweed cellulose instead, but they are not quite there yet.

Soarce makes a seaweed leather alternative and is targeting shoes and car seats, as well as fire-retardant technical fabrics. Carbonwave has developed a leather from Sargassum-derived alginate. In the UK, Uncommon Alchemy is still in the R&D phase, using alginate with a plant-based reinforcement for its leather alternative. 

A look at the market

Last month, leading materials start-up Bolt Threads said it had paused operations for its mycelium-based leather alternative Mylo. Despite raising hundreds of millions of dollars, its attempts to scale into market-ready solutions have struggled since its founding in 2009.


Former COO of Timberland Ken Pucker blames it on ills that would be familiar to any biomaterials startup: 

  1. a lack of investors, whether corporate or venture capital 
  2. too much hype, not enough expectation management 
  3. high barrier to entry: incumbents have invested billions of dollars and decades of research to perfect material properties and drive down costs.

Sustainable fashion marketer Ed Stoner instead faults Bolt for 

  1. collaborating with big brands that move too slow
  2. trying to build their own in-house consumer brand, instead of working with smaller brands or independent designers.

What does this mean for the second generation of seaweed fabrics?


Seaweed growers cannot compete on price with the subsidized oil companies and (livestock) farmers that produce the raw materials for fast fashion today. And it will take decades to build up the expertise to match nylon, polyester and leather manufacturing in cost and scale.

It follows from this that textile innovators should aim for a place where price matters less: high-value niche markets that either

  1. take advantage of the inherent properties of seaweeds, like Soarce’s firefighting gear that uses alginate’s natural flame-retardant properties, or 
  2. target the consumer-segment willing to pay a sustainability premium, like Lululemon.

Incumbent materials also have properties that are very hard to replicate, for instance leather’s ability to improve with age. Algae-based materials are different from petrochemical or animal-based materials. Managing expectations will be another key to success.

Ultimately, material innovation alone cannot clean up the fashion industry; fashion just has too many issues. But fashion can do something for seaweed, by providing one more market for alginates. Rather small for now, up there with underwater robotswelding rod coatings and orthodontic molds. But that could change.

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