Recent high-profile studies that claimed to find microplastics throughout the human body are now being questioned by scientists. They argue that these findings likely stem from contamination and false positives, with one chemist describing the issue as “a bombshell.”
Research suggesting the presence of micro- and nanoplastics in organs like the brain, testes, placentas, and arteries has received widespread media coverage, including in the Guardian. While plastic pollution is undeniably widespread in the environment and present in our food, drink, and air, the potential health impacts of these tiny particles and their chemical additives remain unclear. This uncertainty has fueled a surge in related research in recent years.
However, detecting such minuscule particles in human tissue pushes the limits of current analytical methods. Researchers have expressed concerns to the Guardian that the pressure to publish, sometimes from teams with limited expertise, may have led to rushed results and overlooked standard scientific checks. They emphasize there is no suggestion of misconduct.
The Guardian has identified seven studies that have been formally challenged in their respective journals. A recent analysis also listed 18 studies that allegedly failed to account for how certain human tissues can produce signals easily mistaken for common plastics.
Scientists warn that flawed evidence about microplastic levels in humans could lead to misguided regulations and policies. It could also provide ammunition for plastics industry lobbyists to dismiss legitimate concerns as unfounded. As analytical techniques improve, these doubts raise important questions: what do we truly know right now, and how worried should people be about microplastics in their bodies?
Questioning a Key Study
A widely reported study from February, covered by the Guardian, made the alarming claim that “Levels of microplastics in human brains may be rapidly rising.” Published in a leading journal, it reported an increasing trend of micro- and nanoplastics in brain tissue from autopsies conducted between 1997 and 2024.
By November, this study was formally challenged in the journal by other scientists. In a “Matters arising” letter, they diplomatically noted methodological issues, such as limited contamination controls and a lack of validation steps, which could affect the reliability of the reported concentrations.
One of the letter’s authors, Dr. Dušan Materić, was more direct: “The brain microplastic paper is a joke.” He explained that fat, which makes up about 60% of the brain, is known to create false positives for a common plastic called polyethylene. He and his colleagues suggested that rising obesity rates could be an alternative explanation for the trend the study reported.
Materić believes there are serious doubts about “more than half of the very high impact papers” reporting microplastics in biological tissue.
In response, Prof. Matthew Campen, senior author of the brain study, told the Guardian that this field is in its early stages, with no established rulebook. He stated that most criticism so far has been speculative and not backed by data, and acknowledged the need for ongoing methodological refinement.We have acknowledged the many opportunities for improvement and are focusing our limited resources on developing better tests and data, rather than constantly debating the issues.
‘Bombshell’ Doubts
However, the brain study is not the only one facing challenges. One study, which found that patients with micro- and nanoplastics (MNPs) in their carotid arteries had a higher risk of heart attacks and strokes, was later criticized for not testing blank samples from the operating room. These blanks help measure potential background contamination.
Another study reported MNPs in human testes, suggesting their widespread presence in the male reproductive system. But other scientists disagreed, stating, “It is our opinion that the analytical approach used is not robust enough to support these claims.”
This critique came from Prof. Campen and colleagues, who responded by adapting a sentiment from the TV show Ted Lasso: “[Bioanalytical assays] are never going to be perfect. The best we can do is to keep asking for help and accepting it when you can, and if you keep on doing that, you’ll always be moving toward better.”
Other challenged studies include two reporting plastic particles in blood—with researchers defending their work—and another on detecting them in arteries. A study claiming to find 10,000 nanoplastic particles per liter of bottled water was called “fundamentally unreliable” by critics, a charge the authors disputed.
According to Roger Kuhlman, a former chemist at Dow Chemical, these doubts are a “bombshell.” He said, “This is really forcing us to re-evaluate everything we think we know about microplastics in the body. Which, it turns out, is really not very much. Many researchers are making extraordinary claims, but not providing even ordinary evidence.”
Dr. Frederic Béen of Vrije Universiteit Amsterdam noted that while analytical chemistry has long-established guidelines, specific standards for MNPs are still lacking. “But we still see quite a lot of papers where very standard good laboratory practices that should be followed have not necessarily been followed,” he said.
These practices include measures to prevent background contamination, using blanks, repeating measurements, and testing equipment with samples containing known amounts of MNPs. Without these steps, Béen explained, “you cannot be assured that whatever you have found is not fully or partially derived from some of these issues.”
Biologically Implausible
A key method for measuring MNP mass in a sample involves vaporizing it and analyzing the fumes—a technique called Py-GC-MS. However, this method has faced significant criticism. A January 2025 study led by Dr. Cassandra Rauert, an environmental chemist at the University of Queensland, concluded that Py-GC-MS “is not currently a suitable technique for identifying polyethylene or PVC due to persistent interferences.”
“I do think it is a problem in the entire field,” Rauert told the Guardian. “I think a lot of the concentrations [of MNPs] that are being reported are completely unrealistic.”
She clarified, “This isn’t a dig at [other scientists]. They use these techniques because we haven’t got anything better available to us. But a lot of studies that we’ve seen coming out use the technique without really fully understanding the data that it’s giving you.” She described the failure to use normal quality controls as “a bit crazy.”
The Py-GC-MS process starts by pyrolyzing the sample—heating it until it vaporizes. The fumes are then passed through a gas chromatograph to separate molecules by size, and finally, a mass spectrometer identifies them based on molecular weight. The problem isSome small molecules found in fumes from polyethylene and PVC can also come from fats in human tissue. When preparing human samples for analysis, chemicals are used to break down tissue. If any tissue remains, it can lead to false positives for micro- and nanoplastics (MNPs). Rauert’s paper notes 18 studies that did not account for this risk of false positives.
Rauert also questions studies reporting high levels of MNPs in organs, stating they are hard to believe. “I have not seen evidence that particles between 3 and 30 micrometres can enter the bloodstream,” she said. “Based on what we know about everyday exposure, it’s not biologically plausible that such a large amount of plastic would end up in these organs.”
She added, “It’s really the nano-sized plastic particles that can cross biological barriers and that we expect to find inside humans. But current instruments cannot detect nano-sized particles.”
Further criticism appeared in July in a review study in Deutsches Ärzteblatt, the journal of the German Medical Association. The scientists wrote, “At present, there is hardly any reliable information available on the actual distribution of microplastics in the body.”
Plastic production has increased 200-fold since the 1950s and is projected to nearly triple again to over a billion tonnes per year by 2060. As a result, plastic pollution has surged, with 8 billion tonnes now contaminating the planet, from Mount Everest to the deepest ocean trenches. Less than 10% of plastic is recycled.
An expert review published in The Lancet in August described plastics as a “grave, growing, and underrecognized danger” to human and planetary health. It highlighted harms from fossil fuel extraction for plastic production to its use and disposal, which contribute to air pollution and exposure to toxic chemicals.
In recent years, the infiltration of MNPs into the body has become a serious concern. A landmark 2022 study first reported detecting microplastics in human blood. That study is among the 18 cited in Rauert’s paper and was criticized by Kuhlman.
However, the study’s senior author, Prof. Marja Lamoree of Vrije Universiteit Amsterdam, rejected contamination concerns. “We focused on blood samples because they can be taken freshly, without exposure to plastics or air,” she said.
“I’m convinced we detected microplastics,” she stated. “But I’ve always said the estimated amount could be half or ten times higher.” In response to Kuhlman’s letter, Prof. Lamoree and colleagues said he had “incorrectly interpreted” the data.
Prof. Lamoree acknowledges broader issues in the field. “It’s still a very immature field, and not many labs can perform these analyses well. With solid tissue samples, the difficulty is they are usually taken in operating theatres full of plastic.”
She added, “I think many of the lower-quality analytical papers come from groups like medical doctors or metabolomics scientists who may lack deep analytical chemistry expertise.”
Scientists stress the importance of improving the quality of MNP measurements in the human body. Poor-quality evidence is “irresponsible” and can lead to scaremongering, said Rauert. “We need accurate data to properly inform health agencies, governments, and the public, and to ensure appropriate regulations and policies are put in place.”
“We get many people contacting us, very worried about how much plastic is in their bodies,” she said. “Scientists have a responsibility to report robust science so we don’t unnecessarily scare the general population.”
Rauert also criticized treatments claiming to remove plastics from the body, calling them unproven and potentially harmful.The idea of cleansing microplastics from your blood is considered “crazy” — with some treatments advertised for as much as £10,000. “These claims have no scientific evidence,” she warned, adding that depending on the equipment used, they could even introduce more plastic into a person’s bloodstream.
Materić noted that poorly conducted studies might also help plastics industry lobbyists downplay the known risks of plastic pollution.
On a positive note, Béen highlighted that analytical techniques are advancing quickly: “I think there is less and less doubt that MNPs are present in our tissues. The challenge remains in determining exactly how many or how much. But I believe we are narrowing down this uncertainty more and more.”
Prof Lamoree emphasized the need for collaboration: “I really think we should work together more constructively — with much more open communication — and not try to discredit each other’s findings. We should all move forward instead of fighting one another.”
‘On the safe side’
In the meantime, should the public be worried about MNPs in their bodies?
Given the limited evidence, Prof Lamoree said she couldn’t specify how concerned people should be, but added: “I certainly take some precautions myself to be on the safe side. I really try to use less plastic, especially when cooking, heating food, or drinking from plastic bottles. I also make sure to ventilate my house.”
“We do have plastics in us — I think that’s safe to assume,” said Materić. “But solid proof of how much is still to come. There are also very simple steps you can take to greatly reduce your MNP intake. If you’re worried about water, just filtering it through charcoal helps.” Experts also recommend avoiding food or drinks that have been heated in plastic containers.
Rauert believes most of the MNPs we ingest or inhale are likely expelled by our bodies, but said reducing plastic exposure can’t hurt. She added that it remains crucial to resolve the uncertainty around what MNPs are doing to our health: “We know we’re being exposed, so we definitely want to understand what happens next — and we’ll keep working on it, that’s for sure.”
Frequently Asked Questions
Of course Here is a list of FAQs about a report casting doubt on the discovery of microplastics in the human body designed to be clear and conversational
Beginner Definition Questions
1 What are microplastics
Microplastics are tiny plastic particles smaller than 5mm They come from the breakdown of larger plastic waste synthetic clothing fibers car tires and some cosmetics
2 What was the shocking report everyone was talking about before
Previous widely publicized studies claimed to have found microplastics in human blood lungs placentas and even breast milk suggesting our bodies are widely contaminated
3 What is this new report saying thats different
The new report is critically examining the methods used in those discoveries It suggests that some findings might be due to contamination during the research process itself casting doubt on whether the plastics were truly inside the body originally
4 So are microplastics in our bodies or not
The short answer is we dont know for certain yet It is very likely that we ingest and inhale microplastics but this new report argues that the extent and location of contamination inside our tissues and organs need much more rigorous proof
Advanced ScienceMethod Questions
5 What is contamination in this context and why is it a problem
Contamination means plastic particles got into the sample after it was taken from the human body during collection storage or analysis Because plastic is everywhere in modern labs its extremely challenging to prove a particle found came from inside a patient and not the lab environment
6 Does this mean all the previous research was wrong
Not necessarily It means the findings are now in question and need to be verified with stricter clean room protocols This is a normal and essential part of the scientific processinitial discoveries are scrutinized to ensure they are solid
7 What kind of better evidence do scientists need
Scientists need studies conducted in ultraclean labs with strict controls using methods that can distinguish between external contamination and particles truly embedded in tissues They also need to confirm their findings with multiple independent research teams
