Ten years ago, "microplastics in your body" sounded like a hypothetical. It isn't anymore. Since 2022, three separate research groups have reported finding plastic particles in human blood, placenta and brain tissue — and the brain findings, published in 2024, made international headlines. None of this proves the particles are causing disease. But it's no longer a theoretical concern, and it's part of why we build products without synthetic plastics wherever we reasonably can.
Blood: the first clear signal
In 2022, a Dutch research team led by Heather Leslie published the first study to reliably detect microplastics in human blood, using a method sensitive enough to quantify particles down to 700 nanometres.1 They found plastic particles in the blood of 17 out of 22 healthy adult volunteers — a majority. PET (the plastic used in drink bottles) and polystyrene were the most common polymers detected.
The study didn't look at health effects — it was a proof of detection, not a clinical trial. But it answered a basic question that had been open until then: can ingested or inhaled microplastic actually cross from the gut or lungs into general circulation? The answer, on this evidence, is yes.
Placenta: plastic crossing into the womb
Also in 2021, an Italian team led by Antonio Ragusa reported microplastic particles recovered from human placentas donated by consenting mothers after normal pregnancies and births.2 Particles were found on both the maternal and foetal sides of the placenta, and in the membranes surrounding the foetus.
Again, this was a detection study, not proof of harm to the pregnancy. But the placenta exists specifically to filter what reaches a developing foetus, and finding synthetic particles on both sides of that barrier was, understandably, unsettling to a lot of people — researchers included.
Brain tissue: the 2024 finding
The study that changed the public conversation came in 2024, when a University of New Mexico team led by Alexander Nihart analysed post-mortem human brain tissue and found measurably higher concentrations of microplastics and nanoplastics than in matched liver and kidney samples from the same donors.3 Brain samples from people with a documented dementia diagnosis showed substantially higher plastic concentrations than those without — though the study could not establish whether the plastic contributed to the dementia, was simply easier to detect in degraded brain tissue, or was unrelated to it entirely.
The researchers also compared archived brain tissue samples from 2016 and 2024, and found higher plastic concentrations in the more recent samples — consistent with rising global plastic production and use over that period, though a single comparison like this can't rule out other explanations.
What this doesn't prove
It's worth being precise about the limits of this evidence. None of these studies show that microplastics cause a specific disease in humans. Detection is not the same as harm, and the field is young enough that researchers are still working out which health effects, if any, follow from the levels of exposure people actually experience. Animal and cell-culture studies suggest plausible mechanisms — inflammation, oxidative stress, and the particles acting as a vehicle for other chemicals to hitch a ride into tissue — but translating that into confirmed human health outcomes is a slower, harder process that's still underway.
What has changed is the baseline assumption. Before 2022, it was reasonable to assume ingested or inhaled microplastic mostly passed through the body. That assumption no longer holds. The particles get in, they circulate, and at least some of them appear to accumulate in tissue as sensitive as the brain.
Where the plastic actually comes from
Food packaging, synthetic textiles shedding fibres in the wash, tyre wear dust, and bottled water are the exposure routes with the most evidence behind them so far. Personal care products are a smaller contributor by volume, but they're one of the few sources an individual can control directly and immediately — a plastic-bristled toothbrush worn down over months, or a synthetic sponge or scrubber breaking apart with use, sheds particles into water and, in the case of a toothbrush, directly into the mouth.
It's a small lever next to food packaging and textiles. But it's one we can actually pull, which is the whole reason our toothbrush uses bamboo and horse hair instead of a plastic handle and nylon bristles, and why none of our products rely on synthetic plastic as an ingredient.
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Based on current evidence, avoiding unnecessary synthetic plastic in daily products is a reasonable, low-cost precaution rather than a guaranteed health intervention — there's no current evidence it reverses or prevents a specific condition. We'd rather be upfront about that distinction than oversell what the research actually shows.