Plastic particles are now measurably present in human blood, lung, liver, placenta, breast milk and brain tissue. That part is no longer in dispute — it has been found by separate research groups, in separate countries, with published methods.
What those particles do once they are there is a younger science. Some of it is established, much of it isn't. Every finding on this page carries a label saying which, and a link to the study it came from. Nothing here is a claim we made up.
Measured directly in human tissue, or a clinical outcome study in patients.
Repeated laboratory or animal findings; human evidence is still forming.
Early or contested. Shown so you can follow it, not to draw conclusions from.
Each entry is a published measurement in human tissue, not a projection.
Plastic particles were quantified in the blood of 17 of 22 healthy adult donors, at an average of about 1.6 µg per millilitre. PET, polystyrene and polyethylene were the most common polymers.
Source: Leslie 2022 — Environment International, 163, 107199
Twelve microplastic fragments, 5–10 µm across, were found on both the maternal and foetal sides of human placentas — the first evidence that particles cross into the placental tissue.
Source: Ragusa 2021 — Environment International, 146, 106274
Microplastics were identified in 11 of 13 human lung tissue samples taken during surgery, including in the lower lobes, where researchers had not expected particles of that size to reach.
Source: Jenner 2022 — Science of The Total Environment, 831, 154907
Microplastics were detected in 26 of 34 human breast-milk samples, most commonly polyethylene, PVC and polypropylene.
Source: Ragusa 2022 — Polymers, 14(13), 2700
Six polymer types were found in the liver tissue of patients with cirrhosis; no particles were found in the liver tissue of people without liver disease, which suggests disease may affect how particles accumulate.
Source: Horvatits 2022 — eBioMedicine, 82, 104147
Microplastics were present in every human and dog testis sample examined, and higher polymer concentrations correlated with lower sperm count in the dog samples. The human association was not established.
Source: Hu 2024 — Toxicological Sciences, 200(2), 235–240
Post-mortem brain tissue carried substantially higher plastic concentrations than liver or kidney, mostly as very small polyethylene fragments, and 2024 samples were higher than 2016 samples.
Source: Nihart 2025 — Nature Medicine, 31, 1114–1119
Polyethylene was detected in the carotid plaque of 150 of 257 patients undergoing surgery, with PVC in a further 31.
Source: Marfella 2024 — New England Journal of Medicine, 390(10), 900–910
Up to nine different polymer types were found in the stool of every one of eight participants across three continents — the first direct evidence that people are routinely ingesting and passing plastics.
Source: Schwabl 2019 — Annals of Internal Medicine, 171(7), 453–457
The strongest human outcome finding to date. In a cohort of 257 patients who had plaque surgically removed from the carotid artery and were then followed for about 34 months, those whose plaque contained polyethylene or PVC had a markedly higher rate of heart attack, stroke or death from any cause than those whose plaque did not. It is an association in one cohort, not proof that the particles caused the events — but it is a clinical outcome measured in patients, which is rare in this field.
The most consistent biological mechanism in the literature. Particles in the size range now measured in human tissue provoke inflammatory responses and oxidative stress in cell and animal models, and the plaque cohort found markers of local inflammation in the tissue where particles were present. What is not yet established is the dose at which this matters in an ordinary human body.
Plastic is measurably eaten and passed by everyone tested. Whether the smallest fraction crosses the gut wall in meaningful quantities, and what it does to the gut lining and microbiome, is where most current research sits. The detection of particles in blood shows some fraction does move beyond the gut.
Plastics are not inert: they carry plasticisers, stabilisers, flame retardants and residual monomers, and they adsorb other pollutants from the environment. Several of those additives have far better-established health effects than the particles themselves. Any honest account of the risk includes the chemical load, not just the plastic.
Particles have been found in placenta, breast milk and testis tissue, and infant feeding bottles release millions of polypropylene particles per litre when formula is prepared at recommended temperatures. Presence at these sites is confirmed; harm at these exposure levels is not. This is the area to watch, not the area to draw conclusions from.
Ragusa 2021 · Ragusa 2022 · Hu 2024 · Li 2020
The WHO's own 2022 assessment reaches the same conclusion: exposure is real and widespread, and the evidence base for health effects remains limited. World Health Organization 2022
Only measures with published evidence behind them. No supplements, no detoxes — there is no evidence for either.
Heat is the single biggest documented driver of particle release. Polypropylene infant bottles released an average of 16 million particles per litre when formula was prepared at 70 °C as guidelines advise, and rinsing with cooled water sharply reduced it. The same principle applies to reheating food in plastic containers and to hot drinks in plastic-lined cups.
New imaging found roughly 240,000 detectable plastic fragments per litre of bottled water — around 90% of them nanoplastics, orders of magnitude more than earlier microplastic-only counts. Tap water carries far fewer.
Washing synthetic garments sheds fibres by the gram: measured masses ranged from roughly 0.2 to 4 g per wash depending on garment and machine, with aged garments and top-loaders shedding most. Full loads, cooler cycles and fewer washes all cut it.
Inhalation is a real exposure route — particles were found deep in human lung tissue, and the WHO assessment treats airborne exposure alongside dietary. Fewer synthetic textiles, regular damp dusting and ventilation all lower the airborne load.
All references verified September 2026. See the full source list for the rest of the archive, or how we weigh products.