Do we really have microplastics in our organs, as some studies suggest?

From brains to blood, microplastics have been reported across the human body; now researchers warn that weak methods and contamination may be distorting the evidence and fuelling unnecessary fear

For years now, you and I have been told a deeply unsettling story that tiny fragments of plastic are piling up inside our bodies, lodging themselves in our brains, blood, testes, arteries and even placentas.

 

However, an exclusive investigation by The Guardian has thrown serious doubt on several high-profile studies that reported widespread microplastics in human organs. Scientists now say many of these findings may be the result of contamination, weak laboratory controls, or methods.

Are microplastics really everywhere inside the human body?

We know that plastic pollution is everywhere around us. We inhale it, ingest it through food and water, and encounter it daily through packaging, clothing and household items. But what is still uncertain is how much of this plastic actually stays inside the body and where it ends up.

 

 

Over the past few years, studies claiming to find micro- and nanoplastics in organs such as the brain, testes, arteries, and blood have made global headlines. But scientists now say many of these detections may be false positives.

 

Microplastic particles are tiny, often sitting right at the limits of what current laboratory techniques can reliably measure, the report says.

 

According to researchers who spoke to The Guardian, the rapid growth of this research field has created pressure to publish quickly. In some cases, they say, standard scientific safeguards such as contamination controls, validation checks and repeat testing were not applied rigorously enough. There is no suggestion of misconduct, but there is concern that haste has outpaced accuracy.

 

So far, The Guardian has identified at least seven studies that have been formally challenged in scientific journals, while a separate analysis flagged 18 studies that may have mistaken signals from human tissue for plastic particles.

 

For example, a much-publicised January 2025 study suggested that levels of micro- and nanoplastics in human brains were rising sharply, based on postmortem samples collected over several decades. The headline was alarming.

 

In November 2025, a group of researchers published a formal critique pointing out “methodological challenges”, including weak contamination controls. One of them, environmental chemist Dr Dušan Materić, called the study “a joke because brain tissue is around 60 per cent fat, which can produce chemical signals that look almost identical to polyethylene, one of the most common plastics. Rising obesity levels, Materić suggested, could easily explain the trend the study attributed to plastic.

 

The study’s senior author, Prof Matthew Campen, defended the work, saying the field is still young and methods are evolving. He acknowledged limitations but argued that much of the criticism remains speculative.  ALSO READ | How altered bile acids may influence chronic kidney disease progression

Is this problem limited to one study?

The Guardian report says other high-profile papers have also been challenged.

 

One study linking microplastics in artery plaques to a higher risk of heart attacks and strokes was criticised for failing to test “blank samples” from the operating theatre, a basic step to check background contamination. Another paper reporting microplastics in human testes was described by critics as analytically “not robust enough” to support such claims.

 

Even studies detecting plastic particles in blood and bottled water have been accused of overstating their results, though the authors of those papers strongly dispute the criticisms.

 

To one veteran chemist, Roger Kuhlman, formerly of Dow Chemical, the scale of the problem amounts to a “bombshell”. In his words, many researchers are making “extraordinary claims” without providing “even ordinary evidence”.

Why is the testing itself such a big issue?

Much of the controversy centres on a technique called Py-GC-MS. In simple terms, it works by heating a sample until it vaporises, then analysing the fumes to identify chemical signatures linked to plastics.

 

The catch is that some of those same signatures can also come from fats and other biological materials. If tissue digestion is incomplete, the method can mistakenly identify plastic where none exists.

 

A January 2025 study led by Dr Cassandra Rauert of the University of Queensland concluded that Py-GC-MS is currently not reliable for identifying certain plastics in human tissue. She told The Guardian that many reported concentrations are “completely unrealistic” and, in some cases, biologically implausible.

Does this mean microplastics are not in our bodies at all?

Most scientists agree that some level of microplastic exposure is inevitable. The disagreement is about how much plastic actually stays inside us, where it accumulates, and whether it causes harm.

 

Several experts argue that larger microplastic particles are unlikely to cross into the bloodstream at all. The smaller, nano-sized particles are more concerning biologically, but current instruments cannot reliably detect them. That leaves a large gap between public fear and scientific certainty.

Why does getting this science right really matter?

On one hand, exaggerated or flawed findings can fuel public anxiety and scaremongering. Dr Rauert says her team regularly hears from people terrified about plastic “building up” in their bodies. She is particularly alarmed by expensive treatments claiming to “clean” microplastics from blood, which have no scientific backing and may even introduce more plastic.

 

On the other hand, weak science also risks handing the plastics industry an easy dismissal of genuine environmental and health concerns. If high-profile claims collapse, legitimate risks could be brushed aside as overblown.

 

As scientists told The Guardian, bad evidence can lead to bad policy.

 

So, as of now, there is no clear proof that microplastics inside the body are causing specific diseases. But reducing unnecessary exposure makes sense, and many researchers continue to say they personally avoid heating food in plastic, limit plastic bottles, ventilate their homes, and filter drinking water.  For more health updates, follow #HealthWithBS