Green Tea

ByLaura Shane-McWhorter, PharmD, University of Utah College of Pharmacy
Reviewed/Revised Mar 2024
VIEW PROFESSIONAL VERSION

green tea leaves are steamed but unfermented. Green tea may be brewed and drunk or ingested in tablet or capsule form. Green teaantioxidants, often thought to protect cells from damage by oxygen, mutations, and cancer.

(See also Overview of Dietary Supplements.)

Claims for Green Tea

People take green tea for many reasons, including prevention of cancer and coronary artery disease, as well as treatment of external genital warts. Other reasons are reduction of fat (lipid) levels in the blood, relief of osteoarthritis pain and menopausal symptoms, and enhancement of weight loss, memory, and longevity.

Evidence for Green Tea

Few of the benefits claimed for green tea are supported by strong scientific evidence.  However, topical green tea (applied directly on the wart) may help treat genital warts. Studies have also shown a small but significant loss of weight among users.

Side Effects of Green Tea

Side effects are related to the effects (including the dose) of caffeine. They include insomnia, anxiety, rapid heart rate (tachycardia), and mild tremor. Pregnant women should avoid excessive amounts due to the caffeine

Drug Interactions with Green Tea

Vitamin K in green tea

Green tea

lithium adverse effects may occur.

Green tea

Recommendations for Green Tea

Green tea

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. National Institutes of Health's National Center for Complementary and Integrative Health: Green Tea

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