Microplastics Are Everywhere — And They May Be Inside You

What tiny plastic particles are doing to your body, and what you can do about it

You've probably heard the statistic: the average person ingests about a credit card's worth of plastic every week. But what does that actually mean for your health?

Microplastics — tiny plastic fragments less than 5 millimeters in size — have infiltrated nearly every corner of our world. They've been found in the deepest ocean trenches, on the peaks of remote mountains, in rainfall, in tap water, and in the food we eat. More unsettlingly, scientists have now detected them in human blood, lung tissue, arterial plaque, and even in the placentas of unborn babies.

This is a fast-moving area of research, and scientists are still working to understand the full picture. But what we know so far is worth paying close attention to.

• 5mm Maximum size classified as a microplastic
• ~5g Estimated weekly plastic intake per person — weight of a credit card
• 16,325 Compounds found in plastics, per the 2024 PlastChem Report
  

Microplastic particles come in many shapes, sizes, and colors — most invisible to the naked eye. 

WHERE DO MICROPLASTICS COME FROM?

Plastics don't biodegrade — they break down. Over time, UV light, heat, and physical wear cause larger plastic items to fragment into smaller and smaller pieces. A plastic bottle on a beach doesn't disappear; it splinters into thousands of microplastic fragments, and eventually nanoplastics too small to see with the naked eye.

But weathering isn't the only source. Synthetic textiles like polyester and nylon shed microfibers every time they're washed — a single load of laundry can release hundreds of thousands of fibers into the water supply. Car tires shed plastic particles onto roads, which rain washes into rivers and coastal waters. Food packaging, disposable cups, and plastic wrap all shed particles, especially when heated.

Beyond the particles themselves, there's the chemistry to consider. The 2024 PlastChem Report — a comprehensive global audit — found more than 16,000 compounds present in plastics. Of those, more than 4,200 have been flagged as chemicals of concern, including estrogen-mimicking BPA and endocrine-disrupting phthalates. More than 3,600 of those chemicals remain unregulated anywhere in the world.

WHAT HAPPENS WHEN THEY GET INSIDE US?

Researchers are still working through this question, but the evidence is building fast. Microplastics enter the body primarily through food and water — but also through the air we breathe, particularly indoors where particles accumulate in dust. Fine particles smaller than 10 micrometers can reach deep into the lungs; the smallest can cross into the bloodstream.

Studies have detected microplastics in human lung tissue, blood samples, and even in the tonsil tissue of children. In early 2024, researchers at Stanford Medicine found microplastics not just on the surface of pediatric tonsils, but embedded deep within the tissue — in children who had no particular plastic exposure beyond everyday life.

"What we found is there are definitely microplastics in a high proportion of pediatric tonsil tissue, and they seem to be not only on the surface but also deep within."

— Dr. Kara Meister, pediatric surgeon, Stanford Medicine (2024)

THE CARDIOVASCULAR CONNECTION

One of the most alarming recent findings comes from a landmark 2024 study published in The New England Journal of Medicine. Researchers examined patients undergoing surgery to remove arterial plaque and found microplastics and nanoplastics embedded in the plaque itself. Those with detectable particles in their arteries faced a significantly higher risk of heart attack, stroke, or death in the follow-up period.

Beyond the heart, emerging studies link microplastic exposure to gut microbiome disruption, inflammation, hormonal interference, and — in animal models — increased markers associated with Parkinson's disease and Alzheimer's. Human research is still limited, partly because the field is new and partly because finding an unexposed "control group" is now almost impossible.

SHOULD YOU BE WORRIED?

Concerned, yes — panicked, not yet. Experts are careful to distinguish between correlation and causation, and many of the strongest findings still come from animal studies. But "we don't have definitive proof of harm" isn't the same as "we know it's safe" — and the World Economic Forum's Global Risks Report 2025 ranked pollution, including microplastics, as a top-10 global threat.

Public health researchers draw uncomfortable parallels to earlier moments in science: with lead, asbestos, and certain pesticides, there was a window of uncertainty before the evidence became impossible to ignore. Acting cautiously while the research matures isn't alarmism — it's basic prudence.

WHAT YOU CAN DO RIGHT NOW

You can't opt out of microplastics entirely — they're in rainfall, in the air, in the sea. But several practical steps can meaningfully reduce your personal exposure, especially through diet and daily habits.

Practical ways to reduce your exposure

• Filter tap water — a quality filter reduces particles more than bottled water, which sheds plastic of its own
• Avoid microwaving food in plastic containers; heat accelerates particle shedding — use glass or ceramic instead
• Cut down on single-use plastics for hot food and drinks
• Wash synthetic clothes in a microfiber-catching laundry bag
• Eat more fresh, whole foods with minimal packaging
• Avoid heating food in plastic containers or using plastic cutting boards, which shed thousands of particles when struck by sharp knives. Switch to glass, ceramic, and wood.
• Vacuum and ventilate regularly — indoor dust is a significant source of inhaled plastic fibers
• Choose natural fiber clothing (cotton, wool, linen) where possible

THE BIGGER PICTURE

Microplastics are a symptom of a larger structural problem: we've built a world that runs on a material designed to last forever, and then we discard it. The personal exposure conversation matters — but so does the question of how much plastic gets produced, regulated, and phased out in the first place.

Researchers, health advocates, and policymakers are increasingly aligned on urgency. More funding, faster regulation, and greater transparency from plastic-producing industries are all on the table. Staying informed is its own form of participation in that conversation.

The credit-card-a-week figure is striking precisely because it's so mundane. We didn't choose this exposure — it found us. But the science is now clear enough that ignoring it is no longer a neutral act.

REFERENCES

• Ragusa A. et al. "Plasticenta: First evidence of microplastics in human placenta." Environment International, 2021. doi:10.1016/j.envint.2020.106274
• Leslie H.A. et al. "Discovery and quantification of plastic particle pollution in human blood." Environment International, 2022. doi:10.1016/j.envint.2022.107199
• Marfella R. et al. "Microplastics and nanoplastics in atheromas and cardiovascular events." New England Journal of Medicine, 2024; 390:900–910. doi:10.1056/NEJMoa2309822
• Zimmermann L. et al. PlastChem Report. Research Council of Norway, 2024. plastchem-project.org
• Meister K. et al. Microplastics in pediatric tonsil tissue. Stanford Medicine, 2024. Stanford Medicine summary
• World Economic Forum. Global Risks Report 2025. weforum.org
• Lancet Planetary Health. "Microplastic and nanoplastic pollution and associated potential disease risks." 2025. thelancet.com