Tea made from black tea waste slowed brain tumor cells in a lab dish
Original title: Functional instant tea from black tea waste fiber: effects of extraction conditions on bioactive composition and in vitro anticancer activity.
How far along is this research?
- Lab cells
- Animals
- Review
- Tested in people
This was done on cells in a lab, not in people. It is a very early step.
This was only done on cells in a lab dish.
The short version
A tea drink made from leftover tea fiber killed brain tumor cells in a lab, but this was only done in cells in a dish.
What was studied. Researchers took the fiber left over from making black tea and turned it into instant tea powder. They made it two ways, with hot water and with cold water. Then they dropped the tea onto cancer cells growing in a lab dish, including two kinds of glioblastoma: The fastest-growing type of glioma (grade 4). Treatment usually starts soon after diagnosis: surgery first, then radiation and chemotherapy. See the glossary cells called U87MG and A172.
What they found. The hot water tea had more of the plant compounds called catechins. It hit the U87MG glioblastoma: The fastest-growing type of glioma (grade 4). Treatment usually starts soon after diagnosis: surgery first, then radiation and chemotherapy. See the glossary cells hard. It brought the share of living cells down to 2.7% at a dose of 1.25 mg/mL. The other glioblastoma cells, A172, held up better against it. The hot water tea also slowed prostate cancer cells, and the cold water tea worked better on breast cancer cells.
What this means, and what it doesn't
What it could mean: It means one type of glioblastoma: The fastest-growing type of glioma (grade 4). Treatment usually starts soon after diagnosis: surgery first, then radiation and chemotherapy. See the glossary cell was sensitive to this tea in a dish. That is a starting point for more lab work. It says nothing yet about what tea does inside a person's body.
What it doesn't mean: This does not mean drinking tea treats a brain tumor. The work was done on cells in a lab dish, not in animals and not in people. Cells in a dish get soaked in a set amount of the substance. A person who drinks tea does not get that same amount at the tumor. No one knows if this is safe or useful as a treatment. This is not a cure, and it is a long way from anything a doctor could offer. Do not change your treatment or your diet because of this study.
Source: PubMed, June 30, 2026 · Read the original
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