Plastic detox: what is hiding in your activewear?
A single laundry load of plastic-based clothing can release hundreds of thousands of microfibres into water systems. Activewear — leggings, sports bras, base layers, fleece mid-layers — is one of the most fossil-derived categories in a wardrobe, and it is washed more often than almost anything else. A plastic detox starts with knowing what the fibres are, how they move, and where a fibre genuinely earns its place.
Why most activewear is plastic
Polyester, nylon, elastane and acrylic are fossil-derived polymers. They are lightweight, stretchy, quick-drying and cheap to produce, which is why they dominate gym, yoga and running kit. Textile Exchange’s 2025 Materials Market Report notes that global fibre production continues to rise, with fossil-derived fibres still carrying the largest share of the market. In many wardrobes, plastic-based activewear is the single biggest volume of fossil-derived material worn against the skin.
Recycled polyester — often made from PET bottles — reduces virgin fossil feedstock, but it is still plastic. Laundering studies, including a 2018 activewear and swimwear investigation published in the Journal of Home Economics, have found that recycled polyester textiles also release microplastic fibres during washing. Recycling solves one problem; it does not make the garment biodegradable or fibre-loss-free.
The problem is not that a fossil-derived fibre exists. It is that most kit is made almost entirely from it, by default, in the highest possible volume, with no expectation that it will last.
Microfibres: from fabric to water, soil and body
A 2024 Frontiers in Environmental Science study on functional polyester garments found that household washing releases fibrous microplastics in large numbers. Each wash wears the surface of the yarn, shedding tiny fibres that pass through washing-machine filters and wastewater treatment. The European Environment Agency reports that textile laundering is a major pathway for microplastics entering the aquatic environment, with plastic-based clothing among the largest sources of microfibre pollution.
These fibres do not simply disappear. They have been found in drinking water, Arctic ice, deep-sea sediments, soil and air. Research published in Science of the Total Environment (2024) reviews microplastic exposure in the human body and documents their presence in blood, lung tissue, placenta and stool. The evidence on direct disease causation is still developing, and we are not going to overstate it — but the exposure is real, persistent and growing.
A 2024 review in the Bulletin of the National Research Centre summarises current understanding of micro- and nanoplastic impacts on human health, including oxidative stress, inflammation and cellular interaction. The authors are explicit that the field is evolving. Our reading is a measured one: reduce unnecessary plastic where you reasonably can, and keep what you do own for far longer.
Performance stretch, done responsibly
Here is the honest part. Stretch is not decoration in activewear — it is what makes a garment move with the body, hold its shape through hundreds of wears and stay comfortable when wet. Almost all of that stretch currently comes from elastane, a fossil-derived fibre. There is, at present, no natural fibre that recovers its shape the way elastane does.
So the useful question is not "can we remove every fossil-derived fibre?" but "where does one genuinely earn its place, and which version should we choose?" ROICA, made by Asahi Kasei, is a premium stretch fibre family that includes ROICA EF — a variant produced with recycled content — alongside variants designed for cleaner degradation and certified ingredient transparency. Where TEJ needs stretch, a small percentage of a high-quality, traceable stretch fibre is the intended route, not a fabric that is 80% plastic by weight.
A well-engineered garment with a small share of responsible stretch that fits for a decade is a better outcome than a purely natural one that bags out and gets replaced every year. Durability is a material decision. We would rather say that clearly than market a claim we cannot keep.
What to look for in a cleaner kit
A plastic detox does not mean throwing everything out. It means buying fewer, better pieces and choosing fibres that shed less, last longer and can return to the soil or be recycled at end of life.
- Natural fibres next to skin Wool, organic cotton, linen and Tencel shed biodegradable fibres rather than persistent microplastics. Wool in particular manages moisture and odour without chemical finishes.
- Stretch as a percentage, not a base A few per cent of a good stretch fibre in a natural-fibre fabric behaves very differently from a fabric that is fossil-derived throughout. Read the composition, not the marketing.
- Tight weaves and higher quality Fuzzy, low-quality fleece and brushed plastic-based knits shed the most. Denser knits and woven outer layers release fewer fibres per wash.
- Wash less, wash cooler, use a filter Front-loading machines and lower temperatures reduce fibre release. A microfibre catch bag or external filter can cut what escapes.
- Repair and keep it in use The largest share of a garment’s environmental impact comes from replacing it. A piece that lasts ten years replaces many cheaper alternatives.
Natural first. Stretch only when it earns its place.
This is the decision framework we are working to as the Lab develops. Start with traceable natural fibres, cork and bio-based materials. Add a fossil-derived fibre only where no natural material can meet the performance brief. When one is necessary, choose the lower-impact, recycled or transparently produced option. And prioritise durability and end-of-life over the marketing appeal of a hundred-per-cent-natural claim.
That framework is why our first object, the Heritage Sauna Hat, contains no stretch fibre at all: a felted wool hat has no performance need for it. It is also why we are not promising an activewear range built from nothing but plants. We would rather be specific about trade-offs than quietly hope nobody reads the composition label.
Common questions
- Does all activewear release microfibres?
- Any garment made from fossil-derived fibres — polyester, nylon, elastane, acrylic — can shed microfibres through wear and washing. Natural fibres also shed, but those fibres are biodegradable and do not accumulate as persistent plastics.
- Can activewear ever be completely plastic-free?
- For some pieces, yes — a wool base layer, a linen overlayer, a cotton tee. For anything that needs to stretch and recover its shape, not yet. There is currently no natural fibre that replaces elastane's recovery. An honest answer is that a small percentage of high-quality stretch in a mostly natural fabric is the realistic route today, not a claim of zero plastic.
- What is ROICA?
- ROICA is a premium stretch fibre family made by Asahi Kasei. It includes ROICA EF, produced with recycled content, plus variants developed for cleaner degradation and certified ingredient transparency. It is still an elastane-type fibre, so it is not plastic-free — it is a more traceable, better-documented version of a fibre the garment genuinely needs.
- Is recycled polyester better?
- Recycled polyester reduces demand for virgin fossil feedstock, but it remains a fossil-derived polymer that sheds microfibres. It is a useful transitional material, not a final answer.
- Can a washing-machine filter stop microfibres?
- A good external or built-in microfibre filter can capture a significant portion of fibre loss, especially for fleece and plastic-based knits. It is one of the most effective household interventions.
- Will TEJ release activewear?
- Our first release is the Heritage Sauna Hat, a ritual object made from traceable natural wool. Movement layers sit further out in the vision, and only when the materials meet our standards for performance, longevity and fibre responsibility.
Our first area of focus is thermal and contrast rituals — heat, cold and the transition between them. Start with the object that began TEJ, or read what we are learning about felt.