What's In Your Clothes Is Ending Up In You: A Conversation With Microplastics Scientist Dr. Lisa Erdle from 5 Gyres
A conversation with Dr. Lisa Erdle, ecotoxicologist and Director of Science and Innovation at The 5 Gyres Institute, part of the Plants Over Plastics Collective, our Plastic-Free July interview series.
If you've ever watched dust drift through a sunny window, you've seen microfibers. Tiny colourful flecks, suspended in the light, most of them shed from the clothes in that very room. Dr. Lisa Erdle has spent more than a decade following where they go next. Into lakes and oceans, into the air, and as you've surely heard by now, into our bodies.
Lisa is an ecotoxicologist and the Director of Science and Innovation at The 5 Gyres Institute, one of the most respected research organizations in the plastic pollution field. Her own work spans microfiber sources, where those fibers end up, their toxicity, and the solutions that actually cut emissions, from washing machine filters to the surprising role of clothes dryers.
We invited her onto our Plants Over Plastics interview series to dig into a question that sits close to home for us, given that we've spent fourteen years making textile products worn against the body. What is actually in the clothes we wear every day, and which changes are worth making?
Watch the full interview below, and read on for some of the most consequential takeaways.
Your clothes are shedding, and you're breathing it in
Every garment sheds tiny fibers as you wear it, natural and synthetic alike. The difference is what those fibers become once they're loose. Shed cotton or wool will eventually break down. Shed polyester and nylon are microplastics, and they don't.
Some settle as household dust. Others are small enough to inhale. Researchers now find these fibers deep in the human body, including in lung tissue, where synthetic microfibers are among the most common particle types detected, and even in the olfactory bulb that connects the nose to the brain. In a separate conversation, Aidan Maguire from Plastic Pollution Coalition shared that there's up to a teaspoon of microplastic in our brains already.
"A majority of them are likely synthetic, depending on what you wear," Lisa explained.
Skin contact is a separate pathway. The fibers themselves are too large to pass through skin, but the chemicals riding on them are not. Textiles can carry 5,000 to 6,000 different chemicals across their dyes, finishes, and performance treatments, and sweat can help some of them migrate from fabric into the bloodstream.
This was an unexpected part of the conversation for Rachel (KOOSHOO co-founder) and me as we had expected this conversation to focus on the harms caused by synthetic microfibres and had fully underestimated both the exposure and impact on our health of chemicals in fashion.
"Even something that's a hundred percent cotton can still be up to a third chemicals by weight," Lisa said. In case you're scanning this, I encourage you to pause and read that again. ONE THIRD - yes, 1/3 of your fave tshirt could simply be chemicals (source here)! How good a deal is a $5 t-shirt if 1/3 of that garment's weight is just chemicals that we'd struggle to pronounce, let alone understand their impact on our health?
This isn't to say that the base fibre doesn't matter, because it very much does. Rather, it's saying the two things matter separately. What a garment is made from is one question, and how it was processed is an entirely different one. For example, a 100% cotton label only answers the first.
A cotton label tells you the fibre and nothing else. It says nothing about how that cotton was grown, and conventional cotton is the most heavily sprayed crop on earth, soaked in pesticides that harm pollinators, soil, and farm workers. It says nothing about the dyes used, either, despite the textile industry being known to use 8000 different chemicals across dyeing, printing, and finishing processes (source).
It's for that very reason that are adamant we use only certified organic cotton and OEKO-TEX certified dyes in our KOOSHOO products. OEKO-TEX certified dyes are independently tested to be free of the heavy metals, formaldehyde, and toxic azo compounds found in conventional dyeing, so the colour against your skin or hair is verified safe, not just assumed to be.
Why more than 60% of the world's clothing is now plastic
Textiles are the second most discarded type of plastic on the planet, behind only single-use packaging. Globally, more than 60% of all textiles produced are synthetic, and that share climbs every year.
The reason is economics rather than performance. "It's cheaper and easier to produce plastic clothes," Dr. Lisa said. Polyester and nylon are fast to manufacture and consistent to dye, while natural fibres involve longer, more complex supply chains. Of course, we never actually pay the true cost of polyester at checkout. The price tag on a polyester tee doesn't account for the fossil fuel extraction behind it, the emissions along the way, or the centuries the garment will spend fragmenting after its short working life.
If you read our conversation with Plastic Pollution Coalition, you'll remember why the price gap persists. Subsidized oil and gas keeps synthetic fibres artificially cheap, while plant-based alternatives are often taxed at higher rates. I am still grossed out that when we pay our taxes on money earned running a plant-based hair accessories company, part of those taxes are used to subsidize the materials of the cheap synthetic hair ties we're seeking to replace!
Is recycled polyester actually better?
We have a horse in this race. Back in 2012 we made the world's first hair tie entirely from plants, and the big market incumbents noticed. They were already all-in on plastic, so pivoting to plants wasn't an option, but they weren't about to let everyone chasing a greener choice wander off to a small brand either. So they found a bridge: recycled plastic.
Some went big on it, even building whole recycled-plastic sub-brands around the idea. Others simply printed RECYCLED PLASTIC across their packaging in reassuringly large letters.
None of it has ever felt truthful - or fair to consumers earnestly looking for options that are better for the planet - but we didn't have the data to say otherwise.
So when we had the chance to put the question to a world-renowned toxicologist, someone who did her PhD in microfibres, we jumped at it. You can watch the full exchange in the interview, but here's the heart of what she told us.
Picture a plastic bottle recycled into another bottle. That loop is imperfect and no fix for the global plastic problem on its own, but it can at least repeat, and each turn spares a little virgin plastic.
Now, what happens when that bottle is pulled out and remade into fabric? You get to say "my hair tie is made from recycled bottles," and while that's technically true, it isn't the whole story. That bottle is no longer in the recycling loop because recycled plastic fabric can't be recycled back into more fabric, so those hair ties are the final stop in what could otherwise have been a continuing recycled loop. Once they snap on you - and chances are they were designed to do just that - they're now heading to landfill or waterway to exist forever as microplastics.
"Once you have downcycled a bottle into a polyester garment, it's not going back the other way," Dr. Erdle said.
And it gets worse in the wash. Recycled polyester can actually shed more microfibres than virgin polyester, because the recycling leaves it less durable, so every load sends more microplastic into your water table and back through your own home. Recycled synthetic textiles can also carry chemicals absorbed during their first life as plastic packaging.
Plant-based doesn't automatically mean it breaks down
New biomaterials made from corn, seaweed, and mushrooms genuinely excite Lisa. She just wants you to read past the front of the label.
"You can make a plastic from corn that is chemically identical to a durable fossil fuel-based plastic that does not biodegrade," she said. It will fragment into microplastics and eventually nanoplastics like any other plastic, regardless of its wholesome origins.
Materials that do genuinely break down, like PHA or PBAT, need independent third-party testing to prove it. Plant-based origin and biodegradability are two separate claims, and only one of them is verified by where the material came from. It's the same test Aidan Maguire of Plastic Pollution Coalition gave us earlier in this series: ask what a material does at the end of its life, not just where it began.
How to actually reduce your microplastic exposure from clothing
Lisa's guidance focuses on measurable difference rather than impossible purity, which we appreciated. This isn't about achieving zero, and it isn't about guilt.
Buy secondhand when you can. New garments shed significantly more microfibers than older ones, so a thrifted piece arrives with a smaller shedding footprint from day one.
Wash less often. Denim and wool rarely need a wash after every wear. Lisa's own habit is to hang her jeans to air out rather than run them through the machine, which happens to extend the life of the garment too.
Choose natural fibres for everyday life, and choose them carefully. High-performance synthetics have a legitimate place in genuinely extreme conditions. The school run is not extreme conditions. And the natural option isn't only about avoiding plastic. A brand that has vetted its supply chain, using plant materials grown without heavy chemical inputs and dyes carrying credible certifications, costs more up front, but a well-made natural garment tends to far outlast its synthetic counterpart, and it does so without shedding plastic into your home or leaching a chemical cocktail against your skin for its entire life. Paying once for something that lasts, and lasts cleanly, is a different kind of value than paying repeatedly for something that doesn't.
And trust brands that show their work. There's no chemical ingredient list on a clothing tag, so transparency about supply chains and dye chemistry is the closest thing you have to one. It's a standard we hold ourselves to, and one worth demanding from anyone who makes what you wear.
We already know enough to act
Plastic has only existed since the 1950s, and long-term health research is still catching up. "We don't have great toxicity data for a lot of these chemicals that are in use," Lisa told us, describing a regulatory system in which chemicals stay on the market until proven harmful, rather than being proven safe first. If that sounds familiar, it's the same pattern Sara and Abby described in menstrual care products. The gaps repeat across industries because the system producing them is the same.
Yet Lisa is anything but bleak about it. "There's a lot of really exciting things that are happening," she said, pointing to material innovation, better waste management, and the return of reuse systems that communities have practiced for generations.
The note she left us on was one of agency rather than alarm. We don't have to wait for the science to be complete before we start making better choices, because we already know more than enough to act on today.
Watch the full conversation with Dr. Lisa Erdle on on YouTube here, see pertinent clips on our Instagram feed, and learn more about 5 Gyres' research at 5gyres.org.
This interview is part of the Plants Over Plastics Collective, KOOSHOO's Plastic-Free July series. New episodes drop throughout July. Follow along at @feelingkooshoo on Instagram.