The short answer
Microplastics are almost certainly in your body, and there are plausible ways they could do harm. What is missing is proof that they cause disease at the levels people are exposed to. The World Health Organization's 2022 review concluded the evidence was not enough to determine human health risk, while still recommending that exposure be reduced. Research since then has added worrying signals and also exposed serious measurement problems.
How we rate evidence. Strong means repeated, well-measured findings. Emerging means credible early studies that need confirmation. Contested means other scientists have publicly challenged the method or the numbers.
Heart disease and stroke
Emerging The strongest human evidence so far comes from a 2024 study in the New England Journal of Medicine. Italian researchers examined artery plaque removed from patients having surgery on their carotid arteries. Polyethylene was detected in the plaque of about 58% of patients and PVC in about 12%.
Over roughly three years of follow-up, patients with plastic in their plaque had about 4.5 times the rate of heart attack, stroke or death from any cause. Their plaque also showed higher levels of inflammation markers.
The authors stated that the study does not prove causation. The patients already had artery disease, the people with plastic in their plaque differed in other ways (they were more often smokers and had more diabetes), and the result has not yet been repeated in a larger group. Some critics also question the detection method. Still, it is the first study to connect plastic particles in human tissue with a hard health outcome.
Inflammation, oxidative stress and the gut
Emerging In cell and animal studies, micro- and nanoplastics commonly trigger inflammation and oxidative stress, a type of chemical damage inside cells. Studies in mice also report changes in gut bacteria, damage to the gut lining and effects on the liver and metabolism.
The catch is dose. A 2026 analysis of the toxicology literature found that lab concentrations were often hundreds to millions of times higher than environmental levels, and that harmful effects were rarely seen at realistic doses. Many studies also used perfectly round, fresh polystyrene beads, which are not what people actually swallow. These studies show how harm could happen, not that it does happen in everyday life.
Chemicals carried by plastic
Strong Plastic is not just polymer. It contains thousands of additives, including plasticizers such as phthalates, bisphenols such as BPA, flame retardants and stabilizers. Several of these are established endocrine disruptors, meaning they interfere with hormones, and have been linked to reproductive, developmental and metabolic effects. Microplastic particles can also absorb other pollutants from the environment.
This matters for your choices: the same habits that release particles, especially heating plastic, also increase the chemicals that leach into food.
The brain studies
Contested In February 2025 a study in Nature Medicine reported a median of about 4,800 micrograms of plastic per gram of brain tissue in recent autopsy samples, an amount widely described as "a spoon's worth" of plastic. The finding spread worldwide and was repeated by public officials.
Other chemists challenged it in the same journal later that year. Their main concern is that the method used, which heats tissue and measures the gases released, can mistake the brain's natural fats for polyethylene. Germany's Federal Institute for Risk Assessment also reviewed the study and discussed these limits.
A larger 2026 study in Nature Health tested 191 brain samples using two different methods. It still found plastic in nearly all samples, but at a median of about 50 micrograms per gram in healthy tissue, roughly a hundredth of the earlier figure. That study has also drawn criticism over possible false positives and lab contamination. The honest summary: plastic particles probably do reach the brain, but nobody knows how much, and there is no evidence yet that it causes dementia or other brain disease.
Blood, placenta and other organs
Contested Since 2020, studies have reported plastic particles in human blood, lungs, liver, placenta, breast milk, testes and arteries. A 2022 Dutch study detected plastic in the blood of 17 of 22 healthy volunteers.
In January 2026 a Guardian investigation found that at least seven high-profile studies on microplastics in the human body had been formally challenged in their journals, and that one analysis listed 18 studies that had not accounted for tissue being mistaken for plastic. The original authors dispute some of these criticisms. Most scientists agree that some plastic reaches human tissue. The exact amounts reported in many studies are uncertain.
What about "a credit card a week"?
Contested This popular claim came from a 2019 estimate that gave a range of results, of which 5 grams per week was the highest. Later work suggests real intake by mass is far lower. It is a useful way to grab attention but not a reliable number.
What regulators are doing
In April 2026 the US Environmental Protection Agency proposed adding microplastics, for the first time, as a priority group on its drinking water Contaminant Candidate List. That list does not set limits; it signals a contaminant needs study and may be regulated later. At the same time the Department of Health and Human Services launched a $144 million research program (called STOMP) to measure microplastics in the body and develop ways to remove them. The EU has restricted intentionally added microplastics since October 2023.
So what should you do?
Given real uncertainty, the sensible approach is the one most health bodies take: reduce exposure where it is easy and cheap, and avoid expensive or unproven fixes. The biggest gains come from not heating food or drinks in plastic, drinking filtered tap water instead of bottled, and being careful with baby bottles. Our step-by-step exposure guide ranks the changes by impact.
Frequently asked questions
Can microplastics cause cancer?
There is no direct evidence that microplastics cause cancer in humans. Some lab studies show particles can damage cells and some plastic additives are classified as possible carcinogens. A 2026 study found more plastic near fast-growing brain tumors, but experts note tumors break down the blood-brain barrier, so the plastic may be a result rather than a cause.
Do microplastics affect hormones or fertility?
Plastic additives such as phthalates and bisphenol A are known endocrine disruptors and are linked to reproductive effects. Whether the plastic particles themselves affect fertility in people is not established. Studies reporting particles in testes and placentas exist, but some have been criticized for their measurement methods.
Can you remove microplastics from your body?
There is no proven way to remove microplastics from the body. Treatments sold for this, including some blood-filtering services, have no good evidence behind them. The practical step is to lower new exposure. The US government launched a research program in 2026 to study detection and removal.
Who is most at risk from microplastics?
Infants and young children are the main concern because they take in more per kilogram of body weight, especially from heated plastic bottles and containers, and their organs are still developing. People with existing cardiovascular disease were the focus of the strongest human study so far.
Should I be worried about microplastics?
Concerned enough to make easy changes, but not alarmed. The evidence is not settled, and most people can remove their largest sources, such as heating food in plastic and drinking bottled water, at little cost.
Keep reading
Sources
- Marfella et al. (2024), Microplastics and Nanoplastics in Atheromas and Cardiovascular Events, New England Journal of Medicine
- World Health Organization (2022): Dietary and inhalation exposure to nano- and microplastic particles and potential implications for human health
- Leslie et al. (2022), Discovery and quantification of plastic particle pollution in human blood, Environment International
- Nihart et al. (2025), Bioaccumulation of microplastics in decedent human brains, Nature Medicine
- Li et al. (2026), micro- and nanoplastics in human brain tissue, Nature Health
- German Federal Institute for Risk Assessment (BfR): assessment of the brain microplastics study
- The Guardian (Jan 2026): doubts over studies reporting microplastics throughout the human body
- Zang et al. (2026), Gaps between laboratory experiments and real-world exposure, Environment & Health (summary via News-Medical)
- US EPA (April 2026): EPA and HHS announce actions on microplastics