Green Tea

Made from unfermented tea leaves, green tea is believed to provide numerous health benefits, including lowering cholesterol and promoting weight loss. The tea contains several different polyphenols that may have antioxidant, anti-inflammatory, and anticancer properties. It also contains caffeine, which could increase alertness but may also cause side effects. Although green tea is most commonly used in beverages, it is also a popular ingredient in dietary supplements.

 

What Is Green Tea?

Green tea is made from unfermented tea leaves. While most commonly used in beverages, the tea has become a popular ingredient in dietary supplements. It is claimed to provide a wide variety of health benefits, including weight loss and lower cholesterol.
 
(Click Benefits of Green Tea for more information on what it is used for.)
 

How Does Green Tea Work?

There are numerous known active components in green tea. It contains several different polyphenols. Polyphenols may have antioxidant, anti-inflammatory, and anticancer properties. The tea also contains caffeine, which is why it may increase alertness (but may also cause some side effects).
 

Is It Effective?

It is clearly not the "cure-all" that it is often claimed to be. However, it may be effective for a number of different uses (see Does Green Tea Work? for more information).
 

Dosing Information

It is difficult to recommend a universal dosage, since there are so many different forms of green tea products that may contain differing amounts of the active components. Also, clear dosing recommendations for green tea have not yet been established.
 
(Click Green Tea Dosage for more information.)
 

Side Effects of Green Tea

It can cause several side effects, including:
 
(Click Green Tea Side Effects to learn more, including potentially serious side effects that you should report immediately to your healthcare provider.)
 

Drug Interactions

It can potentially interact with several medications (see Green Tea Drug Interactions).
 

Safety

Normal consumption (through beverages) is probably safe for most people, but medicinal use can cause serious problems. Some people may be more likely to experience problems due to green tea. Therefore, you should talk with your healthcare provider prior to taking it medicinally if you have:
 
  • High blood pressure (hypertension)
  • Iron deficiency anemia
  • Liver disease, such as liver failure, cirrhosis of the liver, or hepatitis
  • Glaucoma
  • Any heart problems
  • Anxiety
  • Any allergies, including allergies to foods, dyes, or preservatives.
     
Also, let your healthcare provider know if you are:
 
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
 
(Click Is Green Tea Safe? for more information, including any available warnings and precautions.)
 

What If I Take a Green Tea Overdose?

Consuming large amounts of it could cause serious problems due to the caffeine content, since a caffeine overdose can be quite dangerous.
 
(Click Green Tea Overdose for more information.) 
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;