Microplastics in the body
Microplastics in the human body: what research shows.
In the last few years, researchers have found microplastics in human blood, lungs, brain tissue, arteries, semen, urine, and stool. The headlines move fast and the science is still young. This is a plain, honest map of what's actually known — and what you can, and can't, test for yourself.
The particles that reach your organs are nanoplastics
Microplastics run from 1 µm to 5 mm. Below 1 µm they're called nanoplastics — and that size is the reason this is a body story at all. Particles small enough to cross the gut lining, enter the bloodstream, slip past the blood-brain barrier, and accumulate inside cells are overwhelmingly nanoplastics. When studies find plastic in blood, placenta, testes, and brain tissue, the fraction that got there is mostly nano. A 2024 Columbia study using stimulated Raman scattering found bottled water held about 240,000 particles per liter — roughly 90% of them nanoplastics. A microplastic count is the visible proxy for a much larger invisible nano load.
Read the full explainer on nanoplastics — what they are, why size changes everything, and how they're measured.
What the research has found
Microplastics detected in human stool for the first time — eight participants, every sample positive.
Schwabl et al., Annals of Internal Medicine
Microplastics found in human blood — the first study to detect plastic particles circulating in the bloodstream.
Leslie et al., Environment International
Microplastics in carotid-artery plaque linked to a 4.5x higher risk of heart attack, stroke, or death over ~34 months.
Marfella et al., New England Journal of Medicine
Microplastics detected in human urine and kidney tissue via micro-Raman spectroscopy.
Science of the Total Environment
Decedent brain tissue found to hold micro- and nanoplastics at far higher concentrations than other organs — the "plastic spoon" study.
Nature Medicine
Microplastics found in human semen and ovarian follicular fluid.
Human Reproduction / press coverage
A note on the science: this field is new, and in 2025–2026 some high-profile body-microplastics studies drew scrutiny over contamination controls and methodology. Treat single dramatic numbers with caution. The broad finding — that microplastics are widespread in the human body — is well supported; the precise quantities are still being worked out.
What you can test for
Can you test for microplastics in your body?
The honest answer: blood and tissue testing is still mostly research-lab territory. Here's what's actually available to a person at home.
Microplastics blood tests, explained
Several companies now sell at-home microplastics blood tests. What they measure, what they cost, and the contamination caveat the marketing skips.
Microplastics urine test
Urine is the most accessible sample there is. A look at the research — and why there's no reliable at-home urine test.
Microplastics in stool
Stool was where microplastics in the body were first confirmed, back in 2018. What the studies found, and what it means.
Start with what you can control.
You can't un-drink the last decade — but you can see what you're drinking now. The $50 at-home kit tests your water for microplastics in about 15 minutes.
Not a medical or diagnostic test. The Water Test makes at-home kits that visualize and count particles in a sample. Nothing here diagnoses or assesses any disease or health condition. For health concerns, talk to a doctor.