What Microplastics From Clothing Actually Do

Synthetic clothing sheds tiny plastic fibers, into the water when you wash it, into the air while you wear it, and into the dust of the rooms where you live. Those fibers are turning up inside human bodies, including in placentas, in breast milk, and in the stool of newborns, where one pilot study measured them at more than ten times the level found in adults. How much harm this does is still being worked out, and it would be easy to overstate. What is not in question is that the fibers shed, that they persist for decades to centuries, and that the plastics carry chemical additives known to interfere with human hormones.

Why this matters, especially if you are dressing a child

Most microplastic coverage is about marine life, which is real but easy to file under someone else's problem. The nearer fact is that the clothing against your skin, and against your child's skin, is a direct source, and the particles it releases do not stay outside the body.

A child meets plastic earlier and more often than an adult does. Exposure begins before birth and continues through bottles, toys, household dust, and the fibers of what they wear and sleep in. Their organs are still forming, and their systems are less able to clear what gets in. The same exposure can mean more for them than for a grown adult.

What sheds, and where it goes

Textiles shed fibers constantly, during wear and especially during washing, and for synthetics the shed material is plastic.

A single wash load of synthetic fleece can release hundreds of thousands of fibers. Mechanically finished polyester such as fleece sheds more than tightly woven nylon, but the direction is the same: synthetic fabric releases synthetic fiber every cycle.

At the scale of the whole system, this is why textiles dominate. Synthetic fibers make up roughly 73% of global fiber production, and the International Union for Conservation of Nature attributes about 35% of primary microplastics in the ocean to synthetic textiles, the largest single source in its accounting.

Washing is not the only route. Synthetic clothing, along with carpet and upholstery, sheds fibers into indoor air, which carries them at concentrations well above outdoor air, and those fibers settle continuously into household dust. That dust is where crawling babies and small children spend their days. The fibers are small enough to inhale.

Sources for this section: PLOS ONE, domestic laundry and microfiber shedding; ScienceDirect, release of microplastic fibers during household washing (2024); Dris et al., textile fibers including microplastics in indoor and outdoor environments; Microplastics in settled indoor dust: implications for human exposure; IUCN primary-microplastics source estimates.

What we know about the body, and what we don't

Microplastics have been detected in human blood, lung tissue, the placenta, and breast milk. Two separate concerns follow from that, and they are not equally established.

The first is the particles themselves. In 2024 the New England Journal of Medicine published a study of patients who had plaque surgically removed from their carotid arteries. Microplastics were found in the plaque of 58.4% of them, and in the roughly three years researchers tracked them afterward, those patients who were found to have microplastics were about 4.5 times as likely to have a heart attack or a stroke, or to die of any cause, as the patients whose plaque held no detectable plastic. While striking, it is only an association and not proof of cause. The study was observational, so it could not show that the plastic drove those events rather than marking some other difference between the two groups.

The second concern is better established, and it is the one that matters most for a growing child: the chemicals that travel with the plastic. Synthetic fibers and the finishes applied to them carry additives such as phthalates, bisphenols, and flame retardants, and microplastics act as carriers that help those compounds into the body, including through contact with skin. Phthalates in particular are recognized endocrine disruptors. They interfere with the hormone signaling that governs growth, metabolism, and reproduction, and the evidence for harm is strongest exactly where the stakes are highest, in pregnancy and early childhood. What remains unsettled is the dose contributed by clothing specifically, and how it compares with plastic's many other routes into a body.

Sources for this section: NEJM, Microplastics and Nanoplastics in Atheromas and Cardiovascular Events (2024); Micro- and Nanoplastics as Disruptors of the Endocrine System (review); Microplastics, Endocrine Disruptors, and Oxidative Stress.

Children carry more of it, and clear less of it

Children are not small adults where this exposure is concerned.

Plastic reaches a baby before birth. Microplastics have been found in the placenta, in amniotic fluid, and in the umbilical cord, and they keep arriving afterward through breast milk, formula, feeding bottles, and dust. In a small 2021 study of stool samples, infants carried more than ten times the concentration of PET, the plastic that polyester is made from, than adults carried. The researchers tied that gap to the plastic products, textiles, and dust that fill an infant's world.

The rest follows from how young children live. They breathe faster for their size, they put more things in their mouths, and they spend their time on the floor where fibers settle. Their metabolizing enzymes and clearance pathways are still developing, so less of what enters gets removed, and the organs it reaches are still under construction.

The honest caveat applies here as much as anywhere. These are early studies, often small, and they document exposure and biological plausibility rather than proven harm. Larger work is needed and is underway. The reasonable reading is not alarm. It is that the youngest people carry the most plastic and are least equipped to handle it, so removing an avoidable source is a sensible thing to do.

Sources for this section: Occurrence of PET and Polycarbonate Microplastics in Infant and Adult Feces, Environmental Science & Technology Letters (2021); Health Implications of Microplastic Exposure in Pregnancy and Early Childhood: A Systematic Review; Microplastics and child health: a scoping review of prenatal and early-life exposure routes.

Natural fibers shed too, but what they shed breaks down

Natural fibers are not zero-shed either. Cotton, linen, hemp, and wool all release fibers in the wash, and by sheer mass cotton can shed more than polyester.

The difference is how long the shed fiber lasts. What a cotton garment sheds is cellulose, and it breaks down. Studies of cotton microfibers report roughly 90% biodegradation within about 40 days in wastewater conditions, and high breakdown in freshwater and soil on similar timescales. A polyester fiber shed into the same environment can persist for decades to centuries, carrying its chemical additives the entire time.

The point is not that natural fibers release nothing, but that they do not leave persistent plastic in your water, your air, and eventually in you and your child's body.

Sources for this section: Cotton Incorporated, biodegradation of cotton microfibers.

What actually reduces the exposure

There are two ways to cut exposure, but they are not equal.

The first is capture: a mesh laundry bag or an in-line washing-machine filter that catches fibers before they reach the drain. These help with the water pathway. They do nothing about the fibers shed while the garment is worn, and they do not change what it is made of.

The second is source reduction: owning fewer synthetic garments, especially in the pieces that sit against skin and cycle through the wash most often, which for a small child means bodysuits, sleepwear, base layers, and bedding. This is the only lever that addresses shedding during wear, shedding during washing, and eventual disposal at the same time.

Capture manages a symptom, while choosing natural fiber removes the source, and that is the practical reason a synthetic-free wardrobe is more than an aesthetic preference.

What this means for our standard

The whole premise of the standard is source reduction. We build a catalog where every product is synthetic-free at the fabric level, so the clothing worn and washed in your home is not shedding persistent plastic into it.

The standard also excludes the chemical finishes that carry the endocrine concern, including phthalates, PFAS, and flame retardants. We screen the fiber and the finish before a product is ever listed, so nothing in the catalog is an exposure you have to manage once it is in your home.

FAQ

Does natural-fiber clothing shed microplastics?

At the fabric level, a genuinely all-natural garment sheds cellulose or protein fiber, not plastic. A natural-fabric garment sewn with polyester thread or finished with a synthetic trim will still shed some plastic, though far less of it than a garment whose entire fabric is synthetic. Fabric is the largest surface area by a wide margin, so it is the first thing to get right, but not the only thing.

If microplastics have not been proven to cause disease, why worry?

For two reasons. The plastics carry additives such as phthalates and bisphenols that are recognized endocrine disruptors, and the concern is greatest during pregnancy and early childhood. Separately, the particles themselves are accumulating in human tissue and were linked to worse cardiovascular outcomes in 2024. It is also a young science. Most of the human findings have arrived only in the last several years, the field is moving quickly, and the current picture is incomplete.

Will a wash bag or a washing-machine filter fix the problem?

A mesh laundry bag, such as the Guppyfriend bag sold for this purpose, or a filter fitted to the machine's outflow, will catch some fibers before they reach the drain. Neither addresses the fibers shed while a garment is worn, and neither changes what the garment is made of.

Is recycled polyester lower-shedding than regular polyester?

No. It is the same plastic fiber and sheds the same way. The recycled feedstock changes where the plastic came from, not what it is.