Green Tea Side Effects — Do They Exist?

Green tea often is promoted as a healthy drink, but in the general public, not much is known about green tea’s side effects. Reports of side effects have been very limited. In fact, the U.S. Food and Drug Administration has categorized green tea as “generally recognized as safe.” However, too much of a good thing can lead to something bad. The same may be true for green tea. Although side effects are relatively rare and minor, it is still good to know what to watch out for. Here are some possible green tea side effects to be aware of:

  • Caffeine sensitivity. Many of the green tea side effects can be attributed to the caffeine content. Though green tea does not have very high quantities of caffeine (only about 3 mg to 30 mg), drinking more than 6 cups per day can lead to some symptoms caused by caffeine: restlessness, palpitations, difficulty sleeping, anxiety, irritability, increased heart rate, and elevated blood pressure. People who have a low tolerance to caffeine may notice the effects more strongly. Drinking smaller quantities of green tea may reduce the symptoms. Or, to cut the caffeine content by 80%, the tea can be infused in hot water for 45 seconds. Discard the liquid. Add more hot water, and steep the tea for 2–3 minutes.
  • Upset stomach. This is a result of improper brewing. Green tea should be brewed with water that is well below the boiling point, preferably between 160–180 degrees Fahrenheit. Steeping tea in water that is too hot will result in increased acidity, which can cause heartburn and an upset stomach.
  • Iron deficiency anemia. Green tea extract has been shown to reduce the body’s absorption of iron by 25%, which may lead to iron deficiency. Therefore, individuals with anemia should be careful when drinking green tea. This side effect can be prevented by drinking tea between meals or by adding lemon.
  • Allergic reactions. Although rare, some people develop adverse allergic reactions to green tea. Reactions require medical assistance and may appear as difficulty breathing, the throat closing up, or swelling of the face, lips, or tongue. Tests can confirm an allergy to green tea.
  • Pregnancy risk. Pregnant women should avoid drinking green tea, especially early during a pregnancy because excess intake has been linked to neural tube birth defects.

Green tea side effects are very rare. The benefits of green tea far outweigh harmful effects. However, it is still wise to be aware of any possible side effects that can occur with the excessive intake of green tea. Drinking 3–4 cups per day is fine, but more than 6 cups may lead to some undesirable effects.