Illustrations: AI-generated
Microplastics are plastic fragments smaller than 5 millimeters, about the size of a pencil eraser, down to particles far too small to see. They come from packaging, synthetic clothing, tires and other plastics breaking down, and they're now in water, food and air. Studies have reported them in human blood, arteries and organs. What they do to our health is still an open question, and some of the most alarming findings are being challenged.
How we reported this guide
✓ Every claim links to the study, agency or news report behind it.
✓ We say when research shows a link rather than proof, and when findings are disputed.
✓ We didn't run our own tests. This guide summarizes published research and government data.
Table of Contents
Where do microplastics come from?
Most microplastics form when larger plastics wear down. Synthetic clothing sheds fibers in the wash and as you wear it. Tires shed particles on the road. Packaging, cutting boards and plastic tea bags can release particles straight into what you eat and drink.
They've been found in fruits and vegetables, seafood, honey and beer, and in farm soils, where plants can take them up.
Heat makes it worse. Plastic tea bags steeped in near-boiling water released billions of particles per cup in a McGill University study, and chopping vegetables on plastic cutting boards can shed particles into food.
Heat speeds things up: plastic mesh tea bags and worn plastic cutting boards can release particles directly into food and drinks.
What are the health risks of microplastics?
The study that put microplastics on many doctors' radar came out in 2024 in The New England Journal of Medicine. Italian researchers examined plaque removed from the neck arteries of patients having surgery. Patients whose plaque contained microplastics or nanoplastics were more likely to have a heart attack or stroke, or to die, over roughly the next three years than patients whose plaque didn't.
Other studies have reported plastic particles in the placenta, testes and brain. A widely covered 2025 study in Nature Medicine reported microplastics in every brain sample it tested and suggested levels were rising over time.
How strong is the evidence: These studies show plastic is present and associated with disease. They don't prove plastic caused it, because people with more plastic exposure may differ in other ways that also affect their health.
Why are some microplastics studies disputed?
In January 2026, The Guardian reported that at least seven high-profile studies finding microplastics in human tissue had been formally challenged by other scientists in the journals that published them. The main concern is measurement. A common method, which heats samples and analyzes the gases they release, can mistake natural fats for polyethylene, one of the most common plastics.
After several studies were challenged over measurement errors, scientists are pushing for stricter testing standards.
That matters most in fatty tissue. The brain is roughly 60 percent fat, and critics argue that may explain why brains appeared to hold so much plastic. The brain study's senior author, Matthew Campen of the University of New Mexico, has defended the work while acknowledging the field is young, and has called the "plastic spoon" comparison a media invention.
Germany's federal risk agency, the BfR, says measurement is still a major source of uncertainty, and scientists are now proposing stricter standards, including checking each sample with several detection methods. None of this means microplastics are harmless. It means the amounts in our bodies, and their effects, aren't pinned down yet.
Why is MAHA concerned about microplastics?
The MAHA Commission's May 2025 report named microplastics among seven chemical groups it wants studied for their role in childhood chronic disease. It cited research on rising levels in brain tissue and on the hormone-disrupting chemicals plastics can carry. Its September 2025 strategy committed HHS, the NIH and the EPA to evaluating the risks of microplastics and synthetics, including in clothing.
Health Secretary Robert F. Kennedy Jr. has made it a signature issue. At the April 2026 launch of a new federal research program, he said "Americans deserve clear answers about how microplastics in their bodies affect their health."
What is the government doing about microplastics?
HHS · RESEARCH
A $144 million research program
On April 2, 2026, HHS launched STOMP, short for Systematic Targeting Of Microplastics, run by its advanced research agency, ARPA-H. It aims to build reliable tests for microplastics in water and human tissue, identify which particles do the most harm, and develop ways to remove them from the body.
EPA · DRINKING WATER
A first step on drinking water
The same day, the EPA added microplastics as a group to its draft list of unregulated drinking water contaminants for the first time. Being on the list doesn't guarantee regulation. It flags a contaminant for research, and critics note many chemicals have sat on the list for years without action.
EPA · MONITORING
Testing is on hold
Advocates also asked the EPA to require utilities to monitor for microplastics. In a 2026 notice, the agency said it wasn't feasible to develop a testing method within the legal deadline, and Zeldin said the technology to test and treat for microplastics is still in development. A former senior EPA water official called it a bait-and-switch.
STATE LAWS
States are acting too
California requires testing and public reporting of microplastics in drinking water, and has proposed adding microplastics to its list of chemicals of concern in consumer products.
How can you lower your exposure to microplastics?
Glass, stainless steel, wood and loose-leaf tea cut down on the plastic that touches your food and drinks.
EASIEST PLACE TO START
Don't heat food or drinks in plastic
Instead: Microwave in glass or ceramic, and let hot food cool before it touches plastic.
Also: Store food in glass or stainless steel.
AT THE TAP
Filter your drinking water
Look for: A reverse osmosis system, which catches most particles.
IN THE KITCHEN
Swap plastic tea bags and cutting boards
Brew loose-leaf tea or use paper tea bags instead of plastic mesh ones, and chop on wood or bamboo instead of plastic cutting boards.
More ways to cut exposure:
Favor cotton, wool and linen, especially for clothes worn close to the skin, and wash synthetics on cold, gentle cycles.
Vacuum with a HEPA filter and dust with a damp cloth, since indoor dust carries plastic fibers.
FAQs
Are there microplastics in the human brain?
A widely covered 2025 study in Nature Medicine reported microplastics in every brain sample it tested. Critics say a common measurement method can mistake natural fats for plastic, and the brain is roughly 60 percent fat, so those amounts may be overstated.
Does the EPA limit microplastics in drinking water?
No. In April 2026, the EPA added microplastics to its draft list of unregulated drinking water contaminants, which flags them for research but doesn't set a limit.
Do water filters remove microplastics?
Reverse osmosis systems catch most particles. Keeping hot food and drinks away from plastic matters too, since heat speeds up how fast plastics shed.
The bottom line
Microplastics are in our water, food and bodies, but how much is there and what it does are still unsettled.
One major study tied microplastics in artery plaque to higher rates of heart attack, stroke and death. Several other headline studies are now disputed over measurement problems.
HHS's $144 million STOMP program aims to build reliable tests and removal methods. The EPA hasn't set any limits.
Keeping hot food and drinks away from plastic is the easiest place to start.
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Sources
Healthy, Again. is health news, not medical advice. Talk to your doctor about any health concern.