Do Tea Bags Dump Microplastics Into Your Cup?

Updated: Sep 10

This is a revision of an article I previously posted on readywellpsych.com. The evidence has moved. The claim level needed to move with it.

I keep hearing the same line after a headline: my tea bags are giving us all cancer.

Some tea bags do release plastic particles into hot water. Researchers have not shown that a daily cup causes cancer, hormone problems, DNA damage, or any other specific disease. Worrying about an extra exposure you can skip is fair. Treating the bag as a catastrophe is not.

Bags can shed particles

A 2026 review looked at 19 studies. Plastic bags, especially polypropylene and nylon, often released a lot of tiny particles into hot water. Some labs counted billions per bag.

A 2025 review put it more simply. In a hot cup, the bag is usually the main source, ahead of the water or the leaves. Some biodegradable and composite bags released particles too.

A Barcelona team later tested three common materials. Polypropylene released about 1.2 billion particles per millilitre, cellulose about 135 million, and nylon-6 about 8 million. Intestinal cells in a dish took some of them up. Useful lab work. Nobody in that experiment sat down and drank the tea.

Why the numbers jump around

I tell patients not to treat any one headline number as a dose.

Labs brew at different temperatures, for different times, with different bags, and they count different particle sizes. Squeezing the bag changes the result. One paper ends up with millions. Another ends up with billions.

Germany's food-risk agency went back to the 2019 study that claimed 11.6 billion particles per bag. It said the method was a poor way to count microplastics. Some of the signal may have been oligomers rather than intact bits of plastic. Some of the material may already have been sitting on the bag. The agency did not expect health harm from those findings. They were arguing with a viral number. They were not calling the bags clean.

A 2025 Birmingham study counted larger particles in more than 150 drinks. Hot tea came in around 60 per litre, about a dozen per cup. That was higher than many cold soft drinks, and higher still in a disposable plastic cup. Different method, different size window, different number. Those results can sit next to the billion-particle papers without one of them having to be fake.

Compostable is still plastic

PLA is often plant-based and sold as compostable. Chemically it is still a polymer. In a 2023 experiment, commercial PLA bags released about a million nanoparticles. Gut cells in a dish absorbed them, especially mucus-producing cells. Some were still there at 72 hours. The model barrier shifted a little, then settled. No one drank the tea and then got their intestines checked.

A paper bag usually beats nylon mesh here. Some paper bags are still heat-sealed with polypropylene. Tea leaves can pick up a little plastic during processing. If you want one change that actually cuts this source, change the bag.

What this does not prove

A 2026 review of 25 studies found microplastics in human blood and several tissues. Some papers tied higher levels to inflammation and other health measures. Almost all of that evidence is observational. The particles could have come from water, dust, food packaging, or clothes. Finding plastic in people does not tell you the tea bag put it there, or that the tea bag made them sick.

What I tell people to do

You do not need to give up tea.

Loose-leaf tea in a steel or glass infuser takes the bag out of the picture. If you like bags, ask whether the bag or the seal contains nylon, PET, polypropylene, or PLA. Compostable does not mean particle-free.

I would not bother brewing cooler on purpose. Heat changes lab counts. Nobody has turned that into a proven safe temperature.

Plastic tea bags add particles you do not need. Whether that extra bit matters for health is still an open question. Switching to loose leaf is a small, reasonable step. The research supports cutting a source you can avoid. It has not shown that your tea bag causes cancer, hormone problems, or DNA damage.

This is general information, not personalized medical advice. Don't start, stop, or change a medication without talking to your own clinician.

References

Sanei ME, Abedini A, Khezerlou A, et al. Tea bags as hidden source of micro- and nanoplastics: a systematic review for food safety. Current Research in Food Science. 2026;12:101425. PMID 42099858.

Jaafarzadeh Haghighi Fard N, Jahedi F, Turner A. Microplastics and nanoplastics in tea: Sources, characteristics and potential impacts. Food Chemistry. 2025;466:142111. PMID 39608112.

Banaei G, García-Rodríguez A, Tavakolpournegari A, et al. The release of polylactic acid nanoplastics (PLA-NPLs) from commercial teabags: Obtention, characterization, and hazard effects of true-to-life PLA-NPLs. Journal of Hazardous Materials. 2023;458:131899. PMID 37354720.

Banaei G, Abass D, Tavakolpournegari A, et al. Teabag-derived micro/nanoplastics (true-to-life MNPLs) as a surrogate for real-life exposure scenarios. Chemosphere. 2024;368:143736.

Hernandez LM, Xu EG, Larsson HCE, et al. Plastic teabags release billions of microparticles and nanoparticles into tea. Environmental Science & Technology. 2019;53(21):12300-12310.

German Federal Institute for Risk Assessment (BfR). BfR assesses study on tea bags and microplastic particles. Communication 029/2025. 5 August 2025.

Al-Mansoori M, Harrad S, Abdallah MA. Synthetic microplastics in hot and cold beverages from the UK market: Comprehensive assessment of human exposure via total beverage intake. Science of the Total Environment. 2025;996:180188. PMID 40752223.

Tran HAA, Ng JJ, Tang DH, et al. Health impacts of micro- and nanoplastics in humans: systematic review of in vivo evidence. Environmental Health. 2026;25:26. PMID 41761215.