Grabbing a hot cup of coffee on the way to work is practically a tradition for many people, but new research shows it could be filled with thousands of microplastic particles. 

What's happening?

Xiangyu Liu, a coauthor of the study published in the Journal of Hazardous Materials: Plastics, wrote for The Conversation to explain the findings. 

He said that whether the cup is made of plastic or just contains a plastic lining, harmful microplastics can leach into coffee, with much more being released as the temperature rises. 

A meta-analysis of 30 peer-reviewed studies conducted by Liu and his colleagues found that polyethylene and polypropylene — two of the most common materials used in coffee cups — released between hundreds and 8 million particles per liter. 

To test how plastic interacts with coffee, they collected 400 coffee cups from Brisbane, including the most common varieties: paper cups lined with a thin plastic coating and cups made entirely of polyethylene designed for cold drinks. The team tested them at both 5 degrees Celsius (41 F) for iced coffee and 60 C (140 F) for hot coffee. 

Both types of cups shed microplastics, but the all-plastic ones released much more than the plastic-lined variety at both temperatures. 

"Daily ingestion of microplastics (MPs) is a growing public-health concern, partially linked to widespread use of single use of plastic cups and containers," the authors wrote in the paper. 

Why are the findings concerning?

While most takeout hot coffee and other beverages are served in plastic-lined cups — which generally shed fewer microplastics, per the study — microplastic intake can add up if someone buys a coffee every day. Researchers stated that if an individual drinks 300 milliliters (about 1.25 cups) of coffee daily in a plastic-lined cup, they could also be downing over 240,000 microplastic particles annually. 

And according to a 2025 National Coffee Data Trends report, American coffee drinkers consume an average of 3 cups per day, suggesting that figure will likely be much higher for some people. 

While Liu noted that scientists are still studying the long-term impacts of microplastics on human health, research on animals or humans has shown that they can increase the risk of dementia, heart and liver disease, and reproductive disorders. 

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As plastics break down in the environment, they contaminate water and soil, making their way into drinking water and food supplies, and eventually into the bodies of humans and animals. Since microplastics are pretty much everywhere, they're almost impossible to avoid, but there are ways to at least reduce exposure. 

How can I keep plastic out of coffee?

Liu recommended using a reusable cup rather than disposable ones, and if you live in the U.S. or Canada, Starbucks and various other coffee shops will fill it up for a small discount. If you can't avoid plastic cups, the lined paper varieties that release fewer microplastics are a better option. You can also ask your barista to make the coffee slightly cooler, or consider brewing more coffee at home, which will boost both your health and your wallet.

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