Field notes on synthetic fibres
Where does polyester go when you wear it?
Polyester doesn't stay on the surface of the fabric. As it wears, washes, and rubs against skin, it sheds microscopic fibres — and researchers are now finding those fibres deep inside the human body.
How the fibres travel
1. Polyester garmentA petroleum-based synthetic fibre, worn against the skin |
2. Sheds microfibresWashing, drying, and everyday friction release tiny plastic fragments |
3. Enters the bodyThrough the skin, the air, or food and water |
4. Reaches the bloodstreamDetected circulating in blood samples in recent studies |
Three entry routes researchers point to
Skin contactVery fine particles may pass through skin, especially with sweat and friction during wear. |
InhalationShed fibres become airborne indoors and can be breathed in over time. |
IngestionFibres shed in laundry water enter waterways, food chains, and drinking water. |
Once in the bloodstream
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17 out of 22
A 2022 study found microplastic particles in the blood of 17 out of 22 healthy adults tested. From there, researchers are tracing where those particles end up next. |
What early research has found
This is a young and fast-moving field. The findings below describe where microplastics — including polyester's PET fibres — have been detected in the body, and what early lab and animal studies suggest. Most human health effects are not yet proven; associations are still being investigated.
Blood & circulationMicroplastic particles have been measured directly in human blood samples, showing the particles can move beyond the gut and lungs into general circulation. |
Placenta & breast milkMicroplastics have been found in placental tissue and breast milk, raising questions researchers are actively studying around exposure during pregnancy and infancy. |
Reproductive tissueA 2024 study detected microplastics, including PET, in every human testis sample examined. Animal studies link particle exposure to reduced sperm count and hormonal disruption. |
Lungs, liver & kidneysParticles have also been identified in lung, liver, and kidney tissue, consistent with inhalation and ingestion as entry routes. |
Cell & immune responseLab studies show microplastic particles can destabilise cell membranes and trigger inflammatory responses in exposed cells and tissue. |
Brain tissueRecent sampling has detected microplastics in human brain tissue, with concentrations reported to be higher in more recent samples than older ones. |