By Afiur
June 18, 2026
Packed with antioxidants, especially catechins, it has been linked to better metabolism, improved heart health and even brain function.
While green tea is hailed as a health beverage, it doesn’t suit everyone. As with many natural foods and beverages, it’s full of active compounds that can have a range of effects on the body.
CanvaIts caffeine content, tannins and bioactive compounds may sometimes produce undesired side effects or interact with some medical conditions.
Green tea has less caffeine than coffee, but it still contains enough to influence if you are sensitive to stimulants. You may be restless, anxious, or have difficulty sleeping after drinking.
If you suffer insomnia or nervousness, your symptoms can worsen with green tea, particularly if taken in high dosages or later in the day.
Tannins in green tea can inhibit the absorption of iron from non-heme, plant-based foods. This can affect if you are low on iron, or are at the risk for iron deficiency anemia.
Green tea has caffeine, which can cross the placenta during pregnancy and potentially affect the developing foetus if consumed in high amounts.
Consuming more than the recommended amount of caffeine when pregnant can lead to complications such as low birth weight or sleep problems in infants.
Tannins in green tea can produce stomach acid, leading to nausea or discomfort. If you suffer from caffeine-sensitive acid reflux or gastritis, your symptoms can react negatively.
Green tea can interact with some medications, including blood thinners, stimulants and certain heart medications. It can change how the drugs function or how the body responds.