Seaweed is one of our planet’s most essential substances, as one of the most enduring and abundant species, dating back more than one billion years. Loaded with trace elements, amino acids, minerals, antioxidants, and vitamins, humans harvest it for everything from medicine and food to fertilizer, fuel, skincare, and…seaweed clothing?
Saltwater seaweed is “Having Its Moment In the Sun”, but it’s not the first time humans have donned kelp clothing. In the 1600s, Japanese textile makers used seaweed fabric to fortify clothing, and in Ancient Rome, it was used to dress wounds.
Thanks to new technologies, the ancient marine plant is now being used for further innovation, like bio-based skis and wearable textiles.
With this sartorial revivial, demand for seaweed fabric is off the charts, with global production increasing by 75% in just ten years. Let’s deep sea dive into kelp fabric to learn more.
Contents: Seaweed Fiber Sustainability
- What Is Seaweed Fabric? Jump to section
- What Is Seaweed Fiber Used For? Jump to section
- How Is Fabric Made From Seaweed? Jump to section
- Sustainability Of Seaweed Fiber Jump to section
- Seaweed Fabric Controversy Jump to section
- Seaweed Clothing Brands Jump to section
What Is Seaweed Fabric?
As we’ve explored with the marine-based sustainable material fish skin leather, the crossover between sustainable fashion and food is becoming more commonplace.
Seaweed, also known as kelp, has long been linked to both sustainability and health benefits, thanks to its nutrient-density and abundance in our oceans. Iron, calcium, iodine, vitamins A,C, E, B12, plus antimicrobial and anti-inflammatory properties and an anti-oxidative capacity make it a rich resource for our wellbeing.
While its cultural roots were mostly as a diet staple in Asia since prehistoric times, modern uses of seaweed for fabric can be traced back to the early twentieth century. The first modern record of seaweed fabric was during World War I, when war manufacturers experimented with different materials to fortify fabric for soldiers, nurses, and other war endeavors.
The fabric was first developed in 2001 by Florida-based Nanonic as a viable alternative to fossil fuel-based synthetic fabrics like polyester and nylon, but only recently began to flourish in popularity.
But what exactly is it?
First, note that kelp fabric is not purely seaweed. It’s a semisynthetic fabric that’s produced by spinning the natural cellulose of beech or eucalyptus trees and seaweed together with special machines to create a soft, stretchy, durable fabric yarn that can be used to weave fabrics.
Beech and eucalyptus trees—the same things used to make modal fabric and lyocell fabric, respectively—are known for their regenerative properties and remain usable post-harvest, meaning they can be sourced again.
Tree cellulose is just part of equation, the other half of course being seaweed, another sustainable resource. The seaweed used for fabric is usually brown Knotted Wrack from Iceland, although some reports also mention Horsetail kelp or Sargassum. The resulting fabric woven from seaweed is biodegradable, absorbent, soft, and breathable.
SeaCell Fabric
Today, the most recognized seaweed fabric supplier is SeaCell, and you’ll find a number of brands are offering SeaCell clothing. According to SeaCell’s most notable manufacturer, German-based Smartfiber AG, the fiber is:
- Nourishing and revitalizing for the wearer’s skin
- Eco-friendly and natural
- Rich in vitamins, minerals, and antioxidants
- Compostable and biodegradable
- Moisture-regulating
- Greatest level of comfort
SeaCell seaweed fabric is 19% seaweed, 81% Lyocell, and bears sustainability certifications from EU Ecolabel, OEKO-TEX, TUV Austria for composting, and TITK. Its manufacturing process also won European Business Awards “Process Innovation” under the Environment category.
What Is Seaweed Fiber Used For?
Seaweed fabric is used primarily in sustainable activewear and loungewear, but is also finding its way into mattresses, home textiles like bedding and towels, and sweaters. In fact, we own a SeaCell sweater and love how it’s still warm yet silkier to the touch.
Many brands adopting the fabric swear by its antimicrobial agent and ability to reduce free radicals and harmful trace elements—although not enough evidence exists to confirm those claims.
Baby clothes and undergarments are also made from the fabric, since it is breathable, soft, lightweight, and moisture-wicking. There was even a revolutionary reusable diaper called ‘Sumo’ made entirely of SeaCell fabric, designed by Luisa Kahlfeldt.
The following are the main beneficial qualities of seaweed clothes:
- Anti-Irritant: SeaCell fibers are smoother and silkier than wool or cotton, and won’t irritate sensitive skin. SeaCell clothing also moves moisture away from your body, preventing bacteria growth.
- Breathability: Like any semisynthetic from the viscose fabric family, its’ 50% more breathable than cotton and is ideal for summer and workout clothing.
- Moisture-Wicking: SeaCell manages to retain 85% of its dryness in wet conditions. This keeps you warm in the cool and cool in the heat.
- Sun Protection: The natural minerals present in the seaweed protect against the sun up to UPF +50. Apparently, the textile eliminates free radicals, which can damage our skin cells.
- Durability: SeaCell is 2x stronger than cotton and viscose while dry and 3x stronger when wet. This means you can machine wash your seaweed fiber clothing repeatedly without them losing shape or durability.
How Is Fabric Made From Seaweed?
SeaCell, the most popular kelp textile, is made from lyocell and a type of brown algae called Knotted Wrack, or more formally Ascophyllum nodossum, which is primarily sourced from Icelandic fjords. The regenerative part of the plant is harvested every four years to minimize environmental impact. Its extraction happens in a way to ensure zero permanent damage to allow it regeneration.
It’s then dried naturally, chopped, and subjected to zero chemical treatments, to ensure its essential substances and trace elements remain.
Next, SeaCell is created via a closed-loop (AKA zero waste) system that recycles about 99% of water and solvents to ensure the fabric is manufactured in a carbon-neutral manner with zero chemicals released. Thanks to an organic amine oxide solvent-spinning process (recognized by FSC as non-toxic), the cellulose is dissolved.
After the washing and retting process, the special solution is filtered and spun through spinnerets to create the filaments (fine threads) that become the blended seaweed yarn.
It’s important to note that seaweed is added to the wood-cellulose lyocell solution, which acts as a “functioning substrate” to the seaweed. According to Smartfiber AG, SeaCell fabric contains 19% seaweed—the rest being lyocell made from wood pulp harvested from beech and eucalyptus trees.
Sustainability Of Seaweed Fiber
It’s no fanta-sea. Seaweed meets all the criteria for a sustainable fabric—it biodegrades, it’s renewable, and it’s carbon-neutral while using minimal water and highly regenerative natural resources. Eucalyptus grows more than a meter per year, while certain species of kelp can grow as much as a meter per day. This means that if sustainably sourced and harvested, producing a material like SeaCell has minimal effect on the plants used.
These beech and eucalyptus trees aren’t just highly regenerative; they also require a minimal amount of water compared to other plants—eucalyptus requiring just 1/10 of the average tree.
Seaweed cultivation can help reduce eutrophication and nutrient pollution (a huge issue due largely to excessive synthetic fertilizer use in the agriculture industry) by absorbing excess nutrients from water, enhancing water quality. It requires no freshwater, arable land, or synthetic inputs to grow, and plays a vital role in carbon sequestration by absorbing CO2 during its growth, mitigating ocean acidification—meaning kelp can also keep climate change at bay.
At the production level, there are yet more advantages, including:
- A zero waste closed-loop process that means no chemicals released into the environment
- Very little water is used (cotton, for example, takes thousands of liters for just a single t-shirt.)
- 100% non-toxic—in contrast to the harmful processes used to make rayon fabric.
- More energy efficient than other textile manufacturing
- Seaweed fabric clothing is compostable and biodegradable
More than anything, however, seaweed has the potential to replace plastics. This is huge, considering most of today’s garments woven from carbon-heavy and plastic-based threads are a disaster to landfills and oceans, where they release harmful microplastics into our waterways, food chains, the environment, and eventually, our bodies.
Seaweed Fabric Controversy
Not to krill your vibe, but we can’t kelp but mention some red flags about this otherwise green material.
Almost two decades ago, Lululemon began using SeaCell. It came under fire after a 2007 New York Times investigation found that the fabric lacked the scientific selling features it claimed, like anti-inflammatory and anti-bacterial properties. They couldn’t even confirm traces of seaweed itself in the fabric.
Today, lululemon has a VitaSea line that still carries the fabric, though any medical claims have been removed. Now, the yoga label focuses on the material’s comfort and breathability.
Meanwhile, brands like Leticia Credidio, Pangaia, Vuori, and Smartfiber continue to tout medicinal benefits of the textile, despite no scientific evidence to back these claims. The regulation of different claims made about sustainability and health benefits of clothing is such an issue in the fashion industry that the EU introduced laws against it in 2022.
But brands selling SeaCell clothing continue to make bold and baseless claims, like:
- SeaCell has an “anti-oxidative capacity eliminates free radicals”
- “SeaCell is known as calming the sympathetic nerve” and helps in “calming emotions and releasing your negative energy”.
- The “fabric structure fosters nutrient transfer”.
- It “absorbs metal ions… through embedded sterilization metal”. (Side note, yes, seaweed itself is known to absorb heavy metals, but there’s no evidence that fabric from seaweed possesses the same ability.)
- Of that its “natural moisture levels enable an active exchange of those restorative substances between the shirt and skin, which can repair cellular damage, reduce inflammation and soothe itchiness”. While we know seaweed has incredible wound healing properties, we’re not sure a fabric with 81% Lyocell and 19% processed seaweed powder can really have these effects.
All that greenwashing aside, the sustainability benefits of seaweed fabric are pretty sea-rious—just don’t buy the bunk about its magical wearable health benefits.
Seaweed Clothing Brands
Ready for your sustainable street style to take a dive into sea-faring fabric technology?
SeaCell and Kelsun by Keelabs (formerly Algiknit) are the major players in among seaweed fabric suppliers, but their knits are being utilized in the designs by a number of fashion brands: