SPECIALTY TOPICS · GUIDE

Microplastics and Nanoplastics Research

What is known about microplastics and nanoplastics in the human body, what the first human studies found, why measurement is hard, and what regulators say about health risk.

Content last updated October 22, 2026. This page has not been medically reviewed.

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Quick answer

Microplastics and nanoplastics have been found in human samples, but finding particles is not the same as showing harm. FDA says there is not enough known about health effects and more research is needed. [1] Labels used: preclinical (cells/animals only), insufficient evidence, mixed, marketing claim. This page does not recommend any product, filter, cleanse or supplement to remove particles.

What the terms mean

FDA describes microplastics as pieces typically less than five millimeters in at least one dimension, and nanoplastics as smaller, typically under one micron; it notes there are no standard size definitions. [1] They come from larger plastics that break down in the environment and may carry chemical additives. [1]

Are they in people?

FDA reports microplastics and nanoplastics have been found in human samples including urine, stool, blood and organs. [1] A 2026 systematic review of 40 observational studies confirmed particles in many human tissues, but found large differences in measurement methods and said potential analytical overestimation limits conclusions about exposure and cause. [2] Label: detection is established in the sense that reports are widespread; accurate amounts are uncertain.

Why measurement is hard

FDA states there are no standardized methods to detect, quantify or characterize microplastics and nanoplastics, so many studies used methods of variable or limited accuracy. [1] Nanoplastics are harder still because measurement methods are not very reliable at those sizes. [1] Numbers in headlines (for example "particles per organ") often depend on the method used.

What human health studies show

Heart and stroke, one cohort. In a prospective observational study of people having carotid artery surgery, 304 patients were enrolled and 257 completed a mean follow-up of about 34 months. Polyethylene was found in the plaque of 150 patients (58.4%), and those with particles detected had a higher rate of heart attack, stroke or death (hazard ratio 4.53, 95% confidence interval 2.00 to 10.27). [3] This is one study, in one surgical population, and observational. It cannot show that particles caused the events, because other differences between the groups could explain it. Label: insufficient evidence of cause.
Broader reviews. A 2026 systematic review of 25 studies of living people found particles in several organ systems linked with inflammation markers and other findings, but rated moderate to high risk of confounding and exposure-measurement bias, and concluded the methods and bias constrain causal inference. [4]
Rapid systematic review. Another review included three human observational studies and 28 animal studies and concluded microplastics are "suspected" to harm reproductive, digestive and respiratory health, based mostly on animals. [5] Animal findings do not transfer to people at everyday exposures. Label: preclinical for most outcomes.
Umbrella review. A review of meta-analyses found none evaluating microplastics or polymers themselves. [6]

How to read a microplastics headline

Ask: Were particles measured by a validated method? Were people followed over time, with a comparison group? Was the outcome a disease or only a lab signal? See Research Hype and Press Releases and Exposure vs Absorbed Dose.

Frequently asked questions

Do microplastics cause disease in humans?

Proper evidence for cause was not found. Reviews describe detection and associations but say bias and measurement problems limit causal conclusions. [4] [2]

Is the carotid plaque study proof of harm?

No. It was observational, so it showed an association between detected particles and later events in one group of surgical patients. [3]

Does FDA say microplastics in food are dangerous?

FDA says current evidence does not demonstrate that levels detected in foods pose a risk, while more research is needed. [1]

Can I remove microplastics from my body?

Proper evidence not found: none of the sources read describes a tested way to remove them from the body. See the detox claims page.

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

What regulators and WHO say

FDA (United States). Current evidence does not demonstrate that the levels detected in foods pose a risk to human health; FDA says it continues to monitor and will act if evidence shows harm. [1]
WHO. WHO reviewed data published to December 2021 and identified research needs and the scope of future work to address current uncertainties. [7]

These are statements as read 2026-10-22; they can change.

Who should check with a clinician

Anyone with a health concern should talk with a clinician rather than relying on a particle test. Consumer tests are covered at Limits of Consumer Environmental and Toxin Testing. Products claiming to "detox" plastics are a marketing claim; see Claim Check: "Detoxifies the Body".

References

Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.