A while ago my colleague showed me an image from a recent study: a human brain from a recent autopsy, sprinkled with colorful spots under electron microscopy. Those spots? Microplastics. Not trace amounts. Not barely detectable levels. Nearly half a percent of the brain’s weight, roughly equivalent to a small plastic spoon dissolved throughout your neural tissue.
As a Neuroscientist and Professor of Neurology, I’ve seen plenty of unwanted things in brains: tau tangles, amyloid plaques, prions. But plastic? This feels different. This is our doing and is increasing by 50% every eight years.
What We Actually Know
Here’s what the science says, stripped of denial and alarmism:
The contamination is real and rising. The University of New Mexico team analyzed 91 human brains from autopsies between 2016 and 2024. Using pyrolysis gas chromatography (basically cooking tissue at 600°C to identify plastics), they found median concentrations of 4,917 μg/g in 2024 brains; up 50% from 3,345 μg/g in 2016. For comparison, liver and kidneys contained 10-30 times less plastic.¹
Size matters, and these are the dangerous kind. Only nanoplastics, particles smaller than 300 nanometers (nm), can breach the blood-brain barrier. That’s about the size of two COVID viruses side by side. These aren’t visible chunks of plastic; they’re plastic dust at the molecular level, small enough to enter individual neurons.²
The mechanism is darkly elegant. Your own immune cells are the Trojan horse. Macrophages (your resident garbagemen that chew up anything that shouldn’t be there; think viruses, bacteria, misfolded proteins) engulf plastic particles, then get stuck in brain capillaries like cellular traffic jams, potentially reducing blood flow to neural tissue.³ Meanwhile, the particles trigger four documented pathways of damage: oxidative stress (cellular rusting), neuroinflammation (brain swelling), blood-brain barrier disruption (compromised defenses), and protein aggregation (the clumping seen in Alzheimer’s). These damage studies are largely done in controlled experimental environments and whether these mechanisms translate to a living human is unclear.
The dementia correlation is striking but not proven. Brains from dementia patients contained 3-10 times more plastic than healthy brains. The knee-jerk reaction is to associate the increase in dementia rates overall with the parallel increase in plastic usage. But here’s the crucial caveat: dementia weakens the blood-brain barrier. The plastic might be accumulating because of the disease, not causing it.¹
What Everyone Gets Wrong
“The FDA says it’s safe!” No, they don’t. They say current evidence doesn’t demonstrate harm. That’s regulatory speak for “we don’t have enough data to act.” Absence of evidence isn’t evidence of absence. The cynic here would say the plastic/petroleum industry is pushing this noncommittal statement but in reality we just do not have enough data yet.
“We can detox from plastics!” The wellness influencers are selling you $200 supplements that do nothing. Your body has no evolved mechanism to eliminate synthetic polymers that didn’t exist until 70 years ago. The fact that plastic levels don’t increase with age suggests some clearance, but we have no idea how it works or how to enhance it. Except maybe for increasing glymphatic flow, see below.
“It’s just correlation!” True, the brain studies are correlational. But the cardiovascular data is getting harder to dismiss. The New England Journal of Medicine study found people with microplastics in their carotid arteries had 4.5 times higher risk of heart attack, stroke, or death over three years. That’s not correlation, that’s tracking actual clinical outcomes.⁴
“Scientists are being alarmist!” Actually, most scientists are being remarkably restrained. The peer-reviewed papers are full of “may,” “could,” and “suggest.” Meanwhile, plastic production is set to triple by 2050. If anything, the scientific community might be under-reacting.
My Take: Why This Seems Different
I’ve spent nearly two decades studying neurotoxins and other things that harm our brains, from blunt trauma to viruses to pesticides to air pollution. Microplastics are different for three reasons:
First, the exposure is universal and accelerating. You can significantly reduce exposure to pesticides by eating organic. You can filter your air. You can test for lead. But plastic is everywhere. It’s in rain, in Arctic snow, in the placentas of unborn babies. And unlike many other pollutants that break down over time, plastics fragment into smaller, more dangerous pieces. We’re not just exposed; we’re marinating in it.
Second, the brain is uniquely vulnerable. Your brain is 60% fat, and plastics are lipophilic (fat-loving). The new research shows plastics preferentially accumulate in myelin, the fatty insulation around neurons that make brain signals go faster and farther. Imagine your neural wiring slowly being infiltrated by plastic particles. Even if they’re not directly toxic, they’re occupying space where brain tissue should be.
Third, we’re running an uncontrolled experiment on human consciousness. Every other neurotoxin we’ve studied existed in nature or has been around long enough to observe multi-generational effects. Nanoplastics in the brain? This is new. We have no evolutionary adaptation, no historical precedent, no long-term data. We’re the test subjects.
But here’s why I’m not panicking: the brain is remarkably resilient. Most people with detectable brain microplastics show no obvious symptoms. The increase from 2016 to 2024, while concerning, still represents less than 1% of brain mass. And some clearance appears to be happening, even if we don’t understand it.
My real concern isn’t today’s levels, it’s the trajectory. If concentrations keep rising 50% every eight years, we’ll hit 1% of brain mass before 2040, 2% by 2052 (Figure). At what point does the brain’s resilience break?
The Action: What to Actually Do
Forget the detox teas (FYI: microplastic exposure is disproportionately high when using tea bags) and meditation apps. Here’s what the evidence supports:
Reduce exposure at the source:
- Use glass or stainless steel for food storage (plastic containers leach, especially when heated and freeze/thawed)
- Choose tap water over bottled (bottled water has 2x more microplastics)
- Minimize ultra-processed foods (they’re wrapped in plastic, made with plastic equipment, and stored in plastic)5
- Skip the synthetic clothing when possible (washing polyester releases millions of particles)
Protect your brain’s existing defenses:
- Exercise increases blood-brain barrier integrity
- Omega-3 fatty acids reduce neuroinflammation
- Sleep activates the glymphatic system (brain’s waste clearance)
- This is probably the most important defense in my opinion.
- Antioxidant-rich foods combat oxidative stress
Think systemically:
- Support legislation limiting single-use plastics
- Choose companies using alternative packaging
- Talk about this (social pressure drives corporate change faster than regulation)
The Bottom Line
We’re all walking around with plastic in our brains. That’s not hyperbole, that’s peer-reviewed fact. The levels are rising. The health implications remain unclear, but the mechanistic evidence suggests real concern.
This isn’t like climate change where the effects are decades away. This isn’t like smoking where only users are affected (for the most part). Every human brain examined in the 2024 cohort contained plastic. Your brain. My brain. Your children’s developing brains.
The question isn’t whether we should be concerned, it’s whether we’ll act on that concern before the experiment concludes itself.
As a neuroscientist, I can tell you what’s in your brain and I’m telling you we need to pay attention to this. Not panic. Not ignore. But pay serious attention to the fact that our most protected organ is being infiltrated by our most ubiquitous pollutant. The mantra in toxicology is “The dose makes the poison” – Paracelsus, 1538. Unfortunately, we are still trying to figure out that calculation.
The brain that’s reading these words contains plastic. Let that sink in. Then let’s do something about it.
Stay Curious,
Andrew
References
- Nihart AJ, Garcia MA, El Hayek E, et al. Bioaccumulation of microplastics in decedent human brains. Nature Medicine. 2025;31(4):1114-1119. Link
- Kopatz V, Wen K, Kovács T, et al. Micro- and nanoplastics breach the blood-brain barrier (BBB): Biomolecular corona’s role revealed. Nanomaterials. 2023;13(8):1404. Link
- Huang H, Hou J, Liao Y, et al. Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction. Science Advances. 2025;11:eadr8243. Link
- Marfella R, Prattichizzo F, Sardu C, et al. Microplastics and nanoplastics in atheromas and cardiovascular events. New England Journal of Medicine. 2024;390:900-910. Link
- Fabiano N, Luu B, Puder D, Marx W. Microplastics and mental health: The role of ultra-processed foods. Brain Medicine. May 2025 Special Issue. Link
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