Last updated: June 20, 2026 · Every finding below is from peer-reviewed research, with the study named inline. For the full set of microplastics numbers, see Microplastics by the Numbers.
Where microplastics have been found in the body
- Blood — in 17 of 22 healthy adults (Leslie et al., 2022).
- Arteries / plaque — linked to 4.5× higher heart-attack & stroke risk (NEJM, 2024).
- Testicles — in all 23 human samples tested (Toxicological Sciences, 2024).
- Placenta & breast milk — exposure begins before birth (Ragusa et al., 2021 & 2022).
- Lungs — including deep lung tissue (Jenner et al., 2022).
- Brain — preliminary, and contested (Nature Medicine, 2025).
Are there microplastics in the human body?
Yes — in every major system researchers have looked at so far. What began with the ocean and seafood is now being detected directly in human tissue and fluids. The pattern across studies is consistent: the smaller the particle (nanoplastics), the more places it reaches. Below, by site.
Microplastics in blood
Found in 17 of 22 healthy adults — about 77%. The first study to quantify plastic in human blood detected particles including PET (the plastic in bottles) and polystyrene (Leslie et al., Environment International, 2022). Because blood reaches every organ, this is the route by which particles can travel through the body.
Microplastics in arteries and the heart
In a 2024 study of 304 patients, those with microplastics in their carotid artery plaque were about 4.5× more likely to have a heart attack or stroke, or to die, over the next ~34 months than those without (Marfella et al., New England Journal of Medicine, 2024). It is an association, not proof of cause — but it is the clearest human-health link to date.
For more, see our deep dive on microplastics and heart health.
Microplastics in the testicles and sperm
Detected in all 23 human testis samples tested. A 2024 study found microplastics in every human (and canine) testicle examined, at levels about three times higher than in animal testes, with PET and PVC most common (Yu, Campen et al., Toxicological Sciences, 2024). Researchers flagged potential consequences for male fertility. See our guide on microplastics and fertility.
Microplastics in the placenta and breast milk
Exposure can begin before birth. The 2021 "Plasticenta" study was the first to find microplastics in human placenta (Ragusa et al., Environment International, 2021), and a 2022 follow-up found them in 26 of 34 breast-milk samples (Ragusa et al., Polymers, 2022). See microplastics during pregnancy.
Microplastics in the lungs
Found in deep lung tissue. A 2022 study detected microplastic fibres and fragments in the lungs of living patients, including in the lower regions of the lung (Jenner et al., Science of the Total Environment, 2022). The likely route is inhalation of airborne fibres from synthetic textiles and household dust.
Microplastics in the brain
Reported in 2025 — but treat this one with caution. A 2025 paper reported microplastics accumulating in human brain tissue, with higher levels in more recent samples (Nihart, Campen et al., Nature Medicine, 2025). It generated huge headlines, but it is preliminary and has drawn methodological criticism (including an image correction), so it should not yet be treated as settled. See microplastics and brain health.
How do microplastics get into the body?
Two main routes: ingestion (bottled water, food, salt, seafood, plastic tea bags) and inhalation (airborne fibres from synthetic fabrics and dust). From the gut and lungs, the smallest nanoplastics can cross into the bloodstream and reach organs. The digestive tract is also a major exposure point — see microplastics and gut health.
What reduces how much enters your body
You can't filter your own bloodstream, but you can cut what goes in. The highest-impact swaps:
See the full picture
For every key microplastics number in one place — water, food, and body — read Microplastics by the Numbers, or get the room-by-room action plan.
Cite this page
Plasticproof. “Microplastics in the Human Body: Where They've Been Found (2026).” Updated June 20, 2026. https://getplasticproof.com/blog/microplastics-in-the-human-body
Frequently Asked Questions
Yes — in blood, lungs, placenta, breast milk, arterial plaque, testicles, and (preliminarily) brain tissue. The first blood study found particles in 17 of 22 healthy adults (Leslie et al., 2022).
Yes — in 17 of 22 healthy adults in the first study to look (Leslie et al., Environment International, 2022).
Yes — a 2024 study found microplastics in all 23 human testis samples tested, raising fertility concerns (Yu, Campen et al., Toxicological Sciences, 2024).
Not proven to cause harm in humans yet, but a 2024 NEJM study found a 4.5× higher risk of heart attack, stroke, or death in patients with microplastics in artery plaque (Marfella et al.).
Mainly ingestion (food, bottled water, salt, seafood) and inhalation (airborne fibres). The smallest nanoplastics can cross from the gut and lungs into the bloodstream.
Sources
- Leslie HA, et al. "Discovery and quantification of plastic particle pollution in human blood." Environment International, 2022. doi.org
- Marfella R, et al. "Microplastics and Nanoplastics in Atheromas and Cardiovascular Events." New England Journal of Medicine, 2024. nejm.org
- Yu X, Campen MJ, et al. "Microplastic presence in dog and human testis." Toxicological Sciences, 2024. ncbi.nlm.nih.gov
- Ragusa A, et al. "Plasticenta: First evidence of microplastics in human placenta." Environment International, 2021.
- Ragusa A, et al. "Microplastics in Human Breast Milk." Polymers, 2022.
- Jenner LC, et al. "Detection of microplastics in human lung tissue." Science of the Total Environment, 2022.
- Nihart AJ, Campen MJ, et al. "Bioaccumulation of microplastics in decedent human brains." Nature Medicine, 2025. nature.com