Microplastics in Tea Bags: A Growing Concern
Experts are raising concerns about the potential health risks associated with everyday tea consumption. Recent studies suggest that the familiar tea bag may be a hidden source of microplastics, tiny plastic particles that could have long-term effects on human health.
When steeped in hot water, tea bags can release billions of microscopic plastic particles into the brewed tea. This has sparked a growing debate among scientists and health professionals about the implications of such exposure. While the full extent of the impact is still under investigation, initial findings are alarming.
A comprehensive review of 19 studies conducted by researchers in Iran and the UK revealed that a single dry tea bag may contain up to 1.3 billion plastic particles. When brewed, this number can increase dramatically, reaching as high as 14.7 billion as the heat breaks down the materials into smaller fragments.
Tea bags made from nylon and PET (polyethylene terephthalate) were found to release particularly high levels of particles when exposed to near-boiling water. Researchers believe that contamination may originate from either the tea bag material itself or from the manufacturing process.
Microplastics have already been detected in human blood, lungs, liver, and other tissues, which raises questions about whether repeated exposure could lead to accumulation in the body over time. Scientists emphasize that while the long-term health consequences are not yet fully understood, laboratory studies have suggested possible links between microplastic exposure and inflammation, oxidative stress, and cellular damage. However, no direct causal link to specific diseases has been confirmed.
One of the main routes of exposure to microplastics is through eating and drinking. Tea brewed with plastic-containing tea bags may therefore be one source of ingestion. Once inside the body, microplastics are small enough to pass through the digestive system, and in some cases, they may interact with tissues. However, the extent of absorption and any long-term effects remain unclear.
A 2024 study from scientists at the Universitat Autònoma de Barcelona found that polypropylene tea bags were among the worst offenders, releasing approximately 1.2 billion particles per millilitre under laboratory conditions. Some of these particles were small enough to potentially interact with cells. Most were absorbed by mucus-producing cells in the small intestine, while some were reported to be small enough to reach the cell nucleus, where genetic material is stored.
Although many of the UK’s most popular tea brands describe their products as “plastic free,” a recent analysis by Which? suggests this may not always be accurate. Of 28 popular brands examined, only four were found to be fully plastic free.
Historically, tea bags were sealed using a small amount of oil-based plastic called polypropylene to keep them intact. Many brands have moved away from this, but it has often been replaced with polylactic acid, or PLA, a plant-derived bioplastic. While PLA is marketed as biodegradable, experts note it is still a form of plastic. Consumer groups say this means some “plastic free” claims may be misleading.
More controversially, some products are also labelled “microplastics free,” despite PLA potentially breaking down into microscopic particles when exposed to hot water.
The analysis identified PLA in own-label tea bags from major supermarkets including Aldi, Asda, Lidl, M&S, Morrisons, Sainsbury’s, Tesco, and Waitrose.
Well-known brands including PG Tips, Tetley, Typhoo, Yorkshire Tea, Teapigs, Brew Tea Company, and Good Earth were also flagged as using plastic-related materials in at least some products.
Which Teabags Contain Microplastics?
Here is a list of brands that have been identified as containing microplastics:
- Aldi
- Asda
- Birchall
- Brew
- Clipper pillow bags
- Dragonfly pillow bags
- Dorset
- Good Earth
- Lancashire
- Lidl
- M&S
- Morrisons
- PG Tips Original
- Sainsbury’s
- Teapigs
- Tesco
- Tetley black tea and Tetley herbal
- Tick Tock
- Thompson’s
- Twinings Tea (everyday tea bags)
- Typhoo
- Waitrose
Yorkshire Tea
as of October 2025
Which? investigation
By contrast, brands such as Dragonfly, Hampstead, Pukka, and some Twinings tea bags were identified as plastic free in certain formats. However, even within brands offering plastic-free options, some tea bags were found to contain PLA in specific designs such as pyramid or pillow-style bags.
Tetley herbal tea bags were among the few products found to contain conventional polypropylene plastic.
Researchers say concern centres on what happens during brewing, when tea bags are exposed to heat, water, and agitation. Some studies suggest PLA may break down more readily in hot conditions, potentially increasing the release of microscopic fragments.
Previous laboratory research from scientists in Spain found that polypropylene tea bags could release extremely high numbers of particles under controlled conditions, some small enough to interact with cells.
Microplastics are currently being studied for potential biological effects, including oxidative stress, inflammation, and disruption of the gut microbiome. However, researchers emphasize that evidence in humans is still limited and the long-term health impact remains uncertain.
Scientists say microplastics are now widespread in the environment and cannot be avoided completely, but exposure may be reduced by switching to loose leaf tea or choosing tea bags confirmed to be plastic-free.
