Most mesh tea bags are made of 20 to 30 percent plastic, which can release microplastics and nanoplastics, causing harmful effects for both human health and the environment. In a study published in the journal Environmental Science & Technology, researchers found that one standard tea bag made with plastic released 11.6 billion microplastics and 3.1 billion nanoplastics into a cup of tea. The particles in the tea matched the nylon and polyethylene terephthalate in the original tea bag.

Safer alternatives include steeping loose teas with a stainless steel or silicone tea strainer, or purchasing tea from brands that offer plastic-free teabags. Organic teas may still have plastic in the tea bag, as the packaging is not overseen by organic-certifying organizations.