Microplastics Have Been Found in Human Brains, Blood and Lungs. Here's What the Study Actually Found.
In February 2025, a study landed that changed the conversation.
Published in Nature Medicine, one of the most respected medical journals in the world, it confirmed something researchers had been working toward for years: microplastics don't just pass through the human body. They accumulate in it. And the brain accumulates more of them than any other organ examined.¹
This isn't speculation. It's peer-reviewed, independently verified, published research. Here's what it actually found.
What the Study Found
The researchers examined brain, kidney and liver tissue from 52 people who underwent forensic autopsy in 2016 and 2024. They used multiple independent analytical methods to confirm their findings.
Microplastics were present in every organ examined:
Brain, liver, and kidney tissue all contained measurable concentrations of microplastics and nanoplastics, primarily polyethylene, the most common plastic polymer.
The brain had the highest concentrations:
Brain tissues harboured significantly higher proportions of microplastics than liver or kidney tissue in both the 2016 and 2024 samples. Under electron microscopy the particles appeared as nanoscale shard-like fragments.¹
Levels are rising over time:
The 2024 brain samples contained roughly 50% more microplastic by mass than the 2016 samples. Researchers also obtained tissue from samples taken between 1997 and 2013 and found the same upward trajectory: plastic concentrations were more than double in the 2016 samples compared to pre-2013, and almost four times higher in the 2024 samples.¹
The increase tracks global plastic production:
The rise in tissue microplastic concentrations mirrors the rise in global plastic production over the same period, suggesting a direct environmental relationship.
What Researchers Are Saying
The scientific community's response to the study has been significant but measured. The finding of microplastics in brain tissue at these concentrations is considered important and credible, though researchers are appropriately cautious about making claims beyond what the data shows.
What the study confirms: accumulation is real, it is increasing, and it is happening across the population regardless of age, sex, or cause of death. What it does not yet establish: specific causal links between microplastic accumulation and particular health outcomes.
That question is the focus of ongoing research across multiple institutions. The fact that brains sampled from people who died with dementia contained on average five times the microplastic levels of other 2024 samples is noted in the paper as a finding that warrants further investigation, without claiming causation.
What This Means for Daily Choices
You can't eliminate microplastic exposure entirely. It's in the air, the water supply, the food chain, and now confirmed in human tissue at measurable concentrations.
What you can do is make deliberate choices about the highest-frequency contact points in your daily routine, particularly the ones involving food and fluid contact with plastic. For most people who train regularly, the shaker bottle is at the top of that list.
Sources
- Nihart, A.J. et al. "Bioaccumulation of microplastics in decedent human brains." Nature Medicine, February 2025. Confirmed presence of microplastics and nanoplastics in human brain, liver and kidney tissue using multiple independent analytical methods. Brain tissue showed the highest concentrations of any organ examined, with a 50% increase between 2016 and 2024 samples, and concentrations almost four times higher in 2024 compared to pre-2013 samples. URL: https://www.nature.com/articles/s41591-024-03453-1
