Glass Bottles Contain More Microplastics Than Plastic Bottles
A French government study found that glass bottles contain five to 50 times more microplastics than plastic bottles, mostly from the painted caps that seal them
Story at-a-glance
A French government study found that glass bottles contain five to 50 times more microplastics than plastic bottles, mostly from the painted caps that seal them
Researchers discovered that the microscopic plastic fragments in glass-packaged drinks matched the chemical makeup of the bottle cap paint, not the glass itself
When bottle caps were pre-cleaned with filtered air and ethanol, microplastic levels dropped by over 60% — showing this problem is avoidable with simple changes
Many people now consume roughly 5 grams of plastic per week — the weight of a credit card — from foods, drinking water, and even from breathing polluted air
Microplastics accumulate in your organs, especially the brain, where they trigger inflammation, obstruct blood flow, and accelerate cognitive decline and neurodegeneration
Glass bottles have long been promoted as the safer, cleaner alternative to plastic. You've probably heard that message dozens of times — choose glass to avoid chemical leaching, plasticizers, or environmental harm. But a recent study found that this advice isn’t as accurate or reliable anymore.
According to new research, drinks stored in glass bottles are loaded with unexpected amounts of microplastics — higher than what’s found in many plastic bottles. If you’ve been shifting your purchases toward glass thinking you’re avoiding plastics entirely, you might need to look closely at what the research says so you can make smarter, safer choices.
French Study Finds Surprising Amounts of Microplastic in Glass Bottles
A recent study conducted by Agence Nationale de Sécurité Sanitaire (ANSES), France’s government agency that is responsible for food, environmental, and occupational health and safety, investigated various local beverages sold in different types of containers to determine how much microplastics they contain. The study, published in the Journal of Food Composition and Analysis, aimed to identify whether the packaging impacts the level of microplastics found in the drinks.1
•The study involved a total of 79 beverage samples — These include still and sparkling water, soda, iced tea, lemonade, beer, and wine. The drinks were packaged across a wide variety of container types, such as glass bottles, plastic bottles, metal cans, cardboard bricks, and cubitainers (large soft containers). This diversity was essential because it allowed the team to compare microplastic content across different packaging materials under realistic, commercially available conditions.
•The researchers implemented strict contamination control measures — Every bottle was opened under a laminar flow cabinet, a sterile environment that eliminates dust and airborne contaminants. All fluids were filtered through a polycarbonate membrane with a pore size of 0.45 microns to trap any microplastic particles larger than that size. This pore size is small enough to capture most microplastics, which typically range from 1 micrometer to 5 millimeters in diameter.
•Across all tested drinks, those stored in glass bottles had the highest levels of contamination — The results found that every liter of beverage stored in glass bottles contains around 100 microplastic particles. On average, these glass-bottled drinks have five to 50 times more microplastic particles than those packaged in plastic or metal.
This finding was consistent across multiple beverage types, especially sodas and lemonades. Surprisingly, wine showed relatively low levels of microplastics even when bottled in glass, likely because many wine bottles use corks instead of painted metal caps (more on this later).
•The results were unexpected, even for the researchers — Iseline Chaib, a Ph.D. student and one of the study authors, said their team "expected the opposite result."
Microplastics originate from various sources. While some are manufactured intentionally, such as microbeads, most microplastics found in the environment are created when larger plastic items like bottles, bags and food packaging break down due to sunlight exposure, weathering, and physical abrasion. These tiny plastic particles are everywhere — even in the beverages you drink.
Painted Bottle Caps Are the Culprit
The researchers specifically identified that the contamination in glass-packaged beverages wasn’t coming from the glass itself — but from the painted metal caps used to seal them.
"We then noticed that in the glass, the particles emerging from the samples were the same shape, color and polymer composition — so therefore the same plastic — as the paint on the outside of the caps that seal the glass bottles," Chaib said.2
•Polyester and alkyd resin polymers were the most commonly identified materials — These were exactly what’s used in industrial paints and coatings for bottle caps. This would also explain why wine bottles, which were sealed with corks, had lower contamination levels of microplastics.
"FTIR analysis of the paint on the metal cap revealed that it was mainly composed of polyester, like the particles isolated from glass bottles, which mainly belong to the polyester class. Therefore, it was hypothesized that these particles could originate from the cap," the researchers said.3
•Microplastics shed during production and storage — The researchers observed the caps under magnification and found that they were covered in tiny scratches — abrasions formed as they scraped against one another during storage. These scratches caused microscopic flakes of paint to detach and fall into the bottle upon sealing. So even if the cap looks perfectly clean and intact outside, inside your drink, fragments are already breaking loose.
•The team confirmed their suspicions through controlled testing — They refilled sterile glass bottles with filtered water and applied new, unused caps. If the caps were not pre-cleaned, the particle count reached an average of 287 microplastic fragments per liter.
But after blowing the caps with filtered air or rinsing them with water and ethanol, contamination levels dropped dramatically to 105 and 86 particles per liter, respectively. However, the researchers note that the microplastic levels only dropped, but are not completely removed.
How Much Plastic Are You Really Ingesting?
Microplastics have infiltrated nearly every corner of the environment. They’re in the soil, oceans, lakes, rivers, and even in the air you breathe. This widespread contamination makes it nearly impossible to avoid exposure entirely.
•Microplastics are everywhere in the human body — Numerous studies have provided evidence on the pervasiveness of microplastics; in fact, these particles have been detected inside living tissue — they are lodged deep within organs, absorbed through your gut, and circulating through your bloodstream. In recent years, scientists have detected microplastic in all kinds of human tissues, including the placenta,4 liver, lungs, kidney, spleen, heart, brain,5 and even your stool.6
•You’re consuming about 5 grams of plastic weekly — This amount was based on research by the World Wildlife Federation (WWF) International, and is about the weight of a credit card.7 Although a significant amount will pass through you and be excreted from your system, some will remain and accumulate in your organs.
•Over time, the numbers add up — According to the WWF’s calculations, you consume about 21 grams of plastic per month — equivalent to one Lego brick.
In a year’s time, you’ve consumed 250 grams, or the size of a full dinner plate’s-worth of plastic. In 10 years, you’ve ingested around 5.5 pounds. And, if you add all that, the amount will reach about 40 pounds in the average lifetime.
And if you think that microplastics linger harmlessly inside your body, the truth is far more sinister. Studies have shown that microplastics are cytotoxic — meaning they are toxic to your cells. One study published in the International Journal of Molecular Sciences found that microplastic particles enter your cells within 24 hours of exposure, and accumulate primarily around the nucleus. As microplastics levels and exposure time increased, cell viability significantly decreased.8
Microplastics Are Linked to Chronic Diseases
Emerging research has uncovered strong connections between microplastic exposure and health problems like high blood pressure, stroke and metabolic dysfunction. Even low-level, everyday exposure has been associated with a higher risk of cardiovascular events.
•Research compares plastic exposure levels in the environment with community disease rates — A recent research looked at the concentration of microplastics in seafloor sediment across 555 U.S. coastal and lakeside census tracts between 2015 and 20199 and compared them with the prevalence of high blood pressure, diabetes, stroke and cancer. They assessed how microplastic pollution stacked up against 154 other environmental and socioeconomic factors.
•Populations who reside in areas with high-microplastic levels had higher rates of chronic illnesses — These include noncommunicable diseases like diabetes, high blood pressure, and stroke. According to researchers, the plastic particles were inhaled or ingested as a result of basic day-to-day activities like drinking water, eating food, or simply breathing.
•Plastic particles are among the top 10 predictors of chronic disease — Microplastic exposure is on par with other high-risk variables like racial minority status or lacking health insurance.
•The more microplastics in your body, the higher your disease risk — The researchers found that regions with very high microplastic levels (over 40,000 particles per square meter of sediment) had the worst disease outcomes. Areas with under 200 particles per square meter of sediment had the lowest outcomes. This shows a clear dose effect.
Another way by which microplastics wreak havoc on your health is by damaging your fertility. Microplastics accumulate in both male and female reproductive organs, contributing to declining fertility rates worldwide. I recommend reading "How Microplastics Affect Your Reproductive Health" for more information on this topic.
Your Brain Is Under Attack by Plastic
As previously mentioned, microplastics travel all over your body, causing harm to your organs. One of the most severely affected by these toxic particles is your brain. This is because microplastics are able to pass through the blood-brain barrier — normally, this protective barrier prevents harmful substances from entering your brain tissues. However, studies found that nanoplastics (particles that measure less than 100 nanometers) are able to cross this barrier in just two hours after entering your body.10
•Microplastics put you at risk of neurodegenerative diseases — According to an animal study published in the Journal of Hazardous Materials, nanoplastics that cross the blood-brain barrier accelerate the spread of beta-amyloid peptides — this is the main pathogenic protein of conditions like dementia and Alzheimer’s disease.11
•Your brain contains more microplastics than other major organs — A recent study published in Nature Medicine analyzed different organ tissues, such as the liver, kidney, and brains, and found that brains are a significant collection point for microplastics. Brain tissues have drastically higher levels of microplastic concentrations. In fact, brain tissue harbored, on average, seven to 30 times more microplastics than the other organs examined.12
•In people with dementia, even higher microplastic concentrations were seen in their brains — The researchers found that microplastic levels in the brains of people with dementia were several times greater than even the already elevated levels found in "normal" brain samples. Read more in "Microplastics Accumulate in Your Brain More Than Other Organs."
•Microplastics cause obstructions in your brain — A separate study found that once microplastics are in the bloodstream, they are quickly engulfed by immune cells. These immune cells then become carriers of these plastic pollutants and are trapped within the narrow capillaries of the brain's cortex, causing physical obstructions that directly impeded blood flow.13 This reduced blood flow in the brain leads to a cascade of neurological and cognitive problems.
Natural Strategies to Eliminate Microplastics Are Being Explored
Studies are now looking at strategies to help the human body filter, trap, and eliminate microplastics before they can spread throughout your other systems. These methods offer a multi-angle approach to help reduce your internal plastic load and support overall health. I’ve recently written a paper discussing these methods in detail, and while it is still under peer-review, I’ve provided the key findings below.
•Cross-linked psyllium could help eliminate microplastics — One key system that plays a role in removing microplastics from your body is your gut. A 2024 study showed that acrylamide cross-linked psyllium (PLP-AM) removed over 92% of common plastic types like polystyrene, polyvinyl chloride (PVC), and polyethylene terephthalate (PET) from water.
Because of its high swelling ability and sticky, gel-like texture, cross-linked psyllium could be adapted to work inside the gut, where it may trap plastic particles before they’re absorbed into the body. While the study was conducted in a water treatment setting, the results are also promising for human health.14
•Chitosan, a natural fiber derived from shellfish, also shows promise for clearing microplastics from your body — A recent animal study published in Scientific Reports found that rats given a chitosan-enriched diet were able to eliminate about 115% of the polyethylene microplastics they were fed, compared to just 84% in the control group.
This suggests that chitosan not only helps bind and eliminate new plastic particles but might even help pull out some that were already absorbed. However, while it's generally considered safe and already used in supplements, people with shellfish allergies are advised to steer clear of it.15
Psyllium and chitosan work through physical adsorption, where hydrophobic (water-repelling) and electrostatic forces stick microplastic particles to the fiber, keeping them from being absorbed. However, one drawback with these binders is that they can also soak up nutrients if not timed carefully. Hence, they need to be used strategically to provide the most benefit, such as ingesting them with processed or packaged foods, which are more likely to contain plastics.
•Certain beneficial bacteria strains can help clear microplastics from the gut — A 2025 animal study found that two specific strains, Lacticaseibacillus paracasei DT66 and Lactiplantibacillus plantarum DT88, were able to bind to and eliminate tiny polystyrene particles in lab tests. These probiotics work by forming protective biofilms that trap plastic particles, making them easier to flush out.16
When combined with dietary fibers like psyllium and chitosan, the result could be a more effective and natural way to sweep microplastics out of the gut before they’re absorbed.
•The liver also plays an essential role in clearing microplastics from the bloodstream — Specialized immune cells in the liver, known as Kupffer cells, help trap these foreign particles and route them into bile for elimination via the intestines. However, while this method may work on smaller plastics, larger ones can linger and build up, especially if your liver function is compromised.
To support this natural detox pathway, researchers are studying the use of compounds like ursodeoxycholic acid (UDCA) and its variant tauroursodeoxycholic acid (TUDCA), which stimulate bile production and improve particle flow out of the liver.
•Researchers are also looking at strategies to enhance autophagy to eliminate microplastics — Autophagy is your body's natural cellular recycling system. Researchers are looking at compounds that can help promote this system, mainly rapamycin and spermidine.
Rapamycin works by inhibiting the mTOR pathway, a nutrient-sensing mechanism that normally suppresses autophagy. When mTOR is turned off, cells ramp up their cleanup efforts, forming membranes that can collect and isolate plastic particles for breakdown or removal. Meanwhile, spermidine is a naturally occurring polyamine found in foods that enhances cellular resilience and supports the clearance of toxic substances.
In lab and animal studies, the combination of spermidine and rapamycin helped reverse mitochondrial dysfunction and reduce oxidative stress caused by microplastics.
The table below summarizes these novel strategies to eliminate microplastics, including their mechanisms of action, how much testing has been done, and important safety considerations. It shows that although several different approaches may be needed, clearing plastics from your body naturally is possible. Of course, reducing your exposure is still the ideal preliminary course of action.
How to Reduce Your Exposure to Microplastics
With more and more information about the damaging health effects of microplastics coming out, it's now more important than ever to take proactive measures to reduce your exposure. Although environmental plastic pollution is now widespread, certain changes will help minimize your microplastic burden and protect your health.
1.Filter your water at home — If you're buying bottled drinks because you don’t trust your tap water, I recommend using a high-quality water filtration system that specifically removes microplastics and heavy metals. I also recommend filling your own glass or stainless-steel bottles at home with clean, filtered water.
2.Boil hard tap water — If you have hard tap water, consider boiling it before using it for cooking or drinking, as hard water traps more microplastics. Recent research shows boiling hard tap water for five minutes removes up to 90% of the microplastics in the water.
3.Rethink your reliance on store-bought bottled drinks — Even brands that market themselves as premium or eco-friendly use plastic liners and caps. Make a habit of preparing your own drinks at home and storing them in safe containers.
4.Switch to wide-mouthed, fully stainless steel or glass containers — Narrow-neck bottles — especially carbonated ones — require strong seals. Those seals are almost always plastic or contain plastic-based glues. Use wide-mouth bottles and jars with stainless steel, ceramic, or bamboo lids.
For carbonated beverages, you’re better off using swing-top glass bottles with rubber gaskets that don’t contain microplastic-shedding components. If you already use glass, inspect the lid lining. If it's soft, white, or peels, that’s likely polyethylene or a plastic-based resin.
5.Use reusable containers — Replace single-use plastic bottles, cups and containers with reusable alternatives made from safer materials like stainless steel or glass.
6.Cut down your exposure by avoiding long storage times — The longer a beverage sits in contact with its container, the more time there is for microplastics to leach out. Heat and acidity accelerate this process. If you have no other choice but to buy a bottled drink, consume it quickly and don’t store it in a hot car, on a windowsill, or anywhere in direct sunlight.
Don’t reuse bottles with plastic caps for storing your own drinks — each reuse increases microplastic release. Transfer beverages into safer containers if you’re going to store them for more than a few hours.
7.Support brands that disclose testing for microplastics — Most companies don't disclose whether they test for microplastic content, let alone what materials they use in their lids and liners. But a few are starting to lead the way by publishing lab results and using fully inert materials like borosilicate glass and metal lids with silicone seals. When possible, support the ones that practice transparency.
For more strategies to help minimize your microplastics exposure, I recommend reading "Fertility Rates Around the World Continue to Decline." Taking these steps will reduce your exposure not just to microplastics, but to the broader cascade of metabolic disruption and mitochondrial damage they cause.
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I would have expected that the plastic bottles would have had similar caps, but I guess not. And/or the manufacturing process doesn't abrade them like the glass bottle ones.
What if caps are designed with paints or materials that leak plastics ?