Key Study (2019, McGill University) Researchers steeped a single plastic ("silken") teabag (made of nylon and PET) at 95°C (brewing temperature) and found it released:

~11.6 billion microplastics

~3.1 billion nanoplastics

per cup. These particles matched the bag's material composition (confirmed via FTIR and XPS spectroscopy). The levels were orders of magnitude higher than microplastics reported in other foods/drinks at the time.

Subsequent studies have found similar (or varying) high releases:

Polypropylene bags: Up to ~1.2 billion particles per milliliter (hundreds of billions per cup, depending on volume).

Nylon-6: ~8 million per milliliter.

Some cellulose/paper bags: Still ~135 million per milliliter (due to coatings, heat-sealing plastics, or fibers).

Even "bioplastic" (e.g., PLA) or composite bags can release significant amounts when steeped in hot water. Heat, agitation, and brewing time increase release.

Not All Teabags

Traditional paper teabags often contain small amounts of plastic (polypropylene) for heat-sealing edges or gluing strings/tags. These can still shed particles, though typically fewer than fully plastic "pyramid" or silken sachets.

Truly plastic-free options exist: Some brands use 100% plant fibers (e.g., abaca, wood pulp, cotton) with stitching or folding instead of heat-sealing/glue. These release far fewer (or negligible) microplastics from the bag itself. Loose-leaf tea with a metal/plastic-free infuser avoids the issue entirely.

Many companies (e.g., some UK brands like PG Tips or Yorkshire) have phased out plastics, but transparency varies. Always check for explicit "plastic-free" or "compostable without plastic" claims, and verify via the brand's site.

Health Context Microplastics and nanoplastics are now ubiquitous (in water, food, air, and human tissues), and tea can be a notable source for regular drinkers. Particles this small can potentially be absorbed by intestinal cells. However, the long-term human health risks of this specific exposure level are still under study—acute toxicity was observed in water fleas, but human data is limited.