Microplastics Are Inside Us. Here Is What the Science Actually Says.
JUMP TO
What microplastics actually are
Where they have been found in the human body
Microplastics have been found in human blood, lungs, livers, kidneys, testes, placentas, breastmilk, the first stool of newborn babies and, most recently, the human brain. The question is no longer whether plastic particles are accumulating inside us. The question is what that means for human health.
The research in this area has accelerated dramatically since 2020. What follows is an honest account of what the science currently shows, what remains uncertain, and what practical steps are supported by the evidence.
What Microplastics Actually Are
Microplastics are plastic particles smaller than 5mm. They come from two sources. Primary microplastics are manufactured at that size — microbeads in personal care products, plastic pellets used in industrial manufacturing, synthetic fibres shed from clothing during washing. Secondary microplastics form when larger plastic items break down through UV exposure, mechanical wear and environmental degradation over time.
Nanoplastics are a subset of microplastics smaller than 1 micrometre — invisible to the naked eye and small enough to cross biological barriers including the blood-brain barrier and the placental barrier. Much of the most alarming recent research involves nanoplastics specifically, because their size allows them to penetrate tissues that larger particles cannot reach.
Globally, an estimated 265 million metric tons of plastic waste are produced each year. Individuals are estimated to ingest between 11,845 and 193,200 microplastic particles annually, with drinking water identified as the primary source of exposure. These figures come from a 2025 review published in Frontiers in Environmental Science.
Where They Have Been Found in the Human Body
The list of human tissues where microplastics have been confirmed keeps growing. As of 2025 they have been detected in:
A 2022 study published in Environment International by Leslie et al. was among the first to detect and quantify plastic particles in human blood. Polyethylene terephthalate and styrene polymers were among those identified, consistent with exposure through food packaging and bottled water.
Microplastics were first confirmed in human placental tissue in 2021, in a study published in Environment International. A 2026 study in ScienceDirect confirmed their presence in multiple fetal organs including the heart, liver and placenta, with the highest particle counts found on the maternal surface of the placenta at 300 particles per sample. This means plastic exposure now begins before birth.
DR LEONARDO TRASANDE
Professor of Paediatrics and Environmental Medicine, NYU
On the impacts of plastic chemicals running from cradle to grave and womb to tomb — and what that means for the next generation.
A landmark study published in the New England Journal of Medicine in March 2024 examined patients undergoing surgery to remove arterial plaque. Those with microplastics in their plaque had a significantly higher risk of heart attack, stroke and death over the following two years compared to those without. This was the first major study to directly link microplastic accumulation in human tissue to adverse health outcomes in living patients.
A 2025 study published in Nature Medicine analysed brain, kidney and liver tissue from post-mortem samples collected in 2016 and 2024. Microplastic concentrations in brain tissue were substantially higher than in other organs, averaging 4,806 micrograms per gram in 2024 samples. Concentrations in brain tissue had increased significantly between 2016 and 2024. Polyethylene was the dominant polymer identified, consistent with food packaging as a likely source.
Microplastics have been confirmed in human testes, in breastmilk and in meconium, the first stool passed by newborns. The presence in testes and breastmilk is particularly significant given the established role of chemical accumulation in reproductive health outcomes and early infant development.
What the Health Research Shows
It is important to be honest about where the science currently sits. Evidence for microplastic accumulation in human tissue is now robust and consistent across multiple independent research groups. Evidence for direct health harm in humans is growing but still developing. Here is what is currently supported:
The New England Journal of Medicine 2024 study provided the strongest direct evidence to date. Patients with microplastics in arterial plaque had a 4.5 times higher risk of cardiovascular events including heart attack, stroke and death compared to those without microplastics in their plaque.
A 2024 systematic review found high quality evidence for microplastic effects on sperm quality. A 2025 systematic review in Archives of Gynecology and Obstetrics documented microplastic effects on female reproductive health including ovarian function and embryo development. The presence of microplastics in testes, placenta and fetal organs establishes a direct pathway for reproductive and developmental exposure.
Multiple cell and animal studies have documented that microplastic exposure triggers oxidative stress and inflammatory responses. A 2025 systematic review of 25 studies on liver health found consistent evidence of oxidative stress, inflammation, mitochondrial dysfunction and lipid metabolism disruption in human liver cell lines exposed to microplastics.
Microplastics carry and concentrate other chemical pollutants on their surfaces, including phthalates, bisphenols and PFAS. They act as what Dr Leonardo Trasande has described as toxic drug delivery systems, transporting endocrine disrupting chemicals directly into tissues they might not otherwise reach in significant concentrations.
Research into microplastic effects on brain tissue is at an earlier stage. The 2025 Nature Medicine study documented accumulation but did not assess cognitive or neurological outcomes directly. Animal studies have shown that polystyrene nanoplastics can promote blood-brain barrier dysfunction. The significance of the concentrations found in human brain tissue is currently under active investigation.
How We Are Exposed
Exposure happens through three main routes:
Drinking water is the primary source. A 2024 study found that one litre of bottled water contained an average of 240,000 plastic particles. Tap water filtered through a quality filter contains significantly fewer particles. Microplastics are also present in seafood, salt, honey, beer and food stored or heated in plastic containers. Heating food in plastic significantly increases the rate at which plastic particles enter food.
Synthetic fibres shed from clothing and furnishings, plastic dust from wear and degradation, and microplastics carried in outdoor air from ocean wave action and industrial sources are all inhaled. Indoor air typically contains higher concentrations of microplastic fibres than outdoor air due to synthetic textiles in furnishings and clothing.
Microplastic absorption through intact healthy skin is considered minimal based on current evidence. However personal care products containing microbeads represent a direct application to skin, and nanoplastics may have greater skin penetration potential than larger particles. The EU banned rinse-off microbeads in cosmetics in 2018, but many products manufactured outside the EU and sold in the UK may still contain them.
What You Can Actually Do About It
No one in 2026 is going to live without any plastic exposure. The goal is meaningful reduction in the areas where the evidence for harm is strongest and where personal choices can make a real difference.
Bottled water contains dramatically higher microplastic concentrations than filtered tap water. A good water filter reduces microplastic particle counts significantly alongside PFAS, chlorine and other contaminants. This is one of the highest impact single changes available. See our Home and Living guide for filter options.
Heat significantly accelerates the rate at which plastic particles and chemical additives migrate into food. Never microwave food in plastic containers, even those labelled microwave safe. Switch to glass or stainless steel containers for storage and reheating.
Plastic chopping boards shed microplastics directly into food during cutting. Wooden or bamboo boards do not. Scratched and worn plastic utensils shed more particles than new ones. Replace them with wood, stainless steel or silicone alternatives as they wear out.
Indoor air contains higher microplastic concentrations than outdoor air in most settings due to synthetic textiles and furnishings. Regular ventilation reduces indoor microplastic fibre accumulation. Vacuuming with a HEPA filter also helps by capturing particles rather than redistributing them.
Washing synthetic clothing releases plastic fibres into wastewater and into the air during tumble drying. A microplastic filter bag for the washing machine captures a significant proportion of these fibres before they enter the water supply. Natural fibre clothing and furnishings shed far fewer plastic particles than synthetic equivalents.
Reduce plastic in your kitchen
Find glass food containers, stainless steel water bottles, wooden chopping boards and microplastic filter bags for washing machines on Amazon.
Shop plastic-free kitchen essentials on Amazon →DR LEONARDO TRASANDE
Professor of Paediatrics and Environmental Medicine, NYU
On why being curious about what we cannot see is the most important thing we can do right now.
The science on microplastics is moving fast. What is already clear is that plastic particles are accumulating inside human bodies at increasing rates and are present in tissues where their effects on health are only beginning to be understood. The precautionary approach is to reduce exposure where it is practical to do so, starting with the highest impact changes first.
Less plastic in your daily life means less plastic in your body.
Sources: Marfella R et al., New England Journal of Medicine (2024) — microplastics in arterial plaque and cardiovascular events | Leslie HA et al., Environment International (2022) — microplastics in human blood | Ragusa A et al., Environment International (2021) — microplastics in human placenta | Campen MJ et al., Nature Medicine (2025) — microplastics in human brain tissue | Ririe et al., Cureus (2025) — systematic review of microplastic health effects | Frontiers in Environmental Science (2025) — microplastic pollution and human health risk assessment | Inam O, Archives of Gynecology and Obstetrics (2025) — microplastics and female reproductive health. Some links on this page are Amazon affiliate links. Purify The World may earn a small commission on purchases made through these links at no extra cost to you.
WANT THE FULL PICTURE?
Dr Leonardo Trasande covers microplastics and the full range of plastic-related chemical exposure in his TEDx talk, including the economic cost of inaction and what he describes as the toxic drug delivery system effect of plastic particles in the body.
Watch the full Dr Leonardo Trasande talk →