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Health Benefits of Green Tea

From bottles, bags, and powders to skin-care products and supplements, this ancient tonic is more popular than ever

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Green tea has been used for centuries in traditional Chinese and Indian medicines to help heal wounds, promote heart health, stabilize blood sugar, and improve digestion and mental function. Now, the ancient tradition of drinking green tea for good health is getting a modern makeover.

More than 4,000 scientific studies have shown that green tea contains antioxidants and other substances that help lower cholesterol and protect against cancer, heart disease, diabetes, gum disease, and bacterial and viral infections. For example, an 11-year study of 40,000 people in Japan, published in the Journal of the American Medical Association, found significant differences in the health and lifespan of those who drank less than one cup of green tea daily compared to those who drank more than five cups. Heavy green tea drinkers were up to 31 percent less likely to die from heart disease and up to 42 percent less likely to die from stroke.

Health Components of Green Tea

Today, green tea is the most popular antioxidant ingredient in natural skin care products. It helps reduce damage from exposure to sun, slow down aging, and clear up skin conditions such as rosacea. And as a drink in place of sugary sodas, green tea is certainly a healthier option.

In supplements, two components of green tea show a great deal of promise: EGCG (epigallocatechin gallate), a powerful antioxidant, and theanine, an amino acid that has a calming effect and, surprisingly, also improves attentiveness.

EGCG (epigallocatechin gallate)

EGCG-EGCG is considered the chief active ingredient responsible for green tea’s health-enhancing benefits. It has also been tested in many studies as a weight-loss aid. A review of research, published in The Journal of Nutrition, found that in both animal and human trials, the concentration of EGCG and other antioxidants in green tea correlate with its effect on body weight.

In observational studies that examined more than 5,000 people, consuming EGCG and other antioxidants in green tea correlated with weight loss or lack of weight gain, regardless of other factors. These active ingredients in the tea reduce fat storage-to a small but significant degree-by improving the metabolism of sugars and fats.


Theanine, also listed as L-theanine on labels, theanine is an amino acid found naturally in green tea (although it’s more concentrated in theanine supplements). It helps counteract stress, calming the nervous system by reducing levels of the stress hormones cortisol and epinephrine, and improves sleep without causing grogginess. It can be taken at any time of day, or during the night if you wake up and can’t get back to sleep. During the day, it has a relaxing effect without interfering with mental function. In fact, its dual ability to enhance sleep and reduce stress can improve the ability to focus.

A study published in Alternative Medicine Review tested a form of theanine-Suntheanine-on 93 boys ages 8-12 that had ADHD. For six weeks, the boys took either a placebo or 200 mg of Suntheanine twice daily. Those taking the theanine supplement experienced better quality of sleep, a key factor in improving attention during the day. Other studies have found that theanine improves sleep and reduces daytime stress in healthy adults.

How to Benefit from Green Tea

For health maintenance and protection against disease, these are typical recommendations:

Green Tea: 2-3 cups daily. One cup of green tea (2 grams of tea brewed in approximately 6 oz. of water) contains 70-160 mg of EGCG.

EGCG: 50-75 mg, 3 times daily. Labels for green tea extracts typically list EGCG as a percentage, which can range from 50-94 percent. For example, 100 mg of an
extract with 50 percent EGCG delivers 50 mg
of EGCG.

Theanine: 50-200 mg during the day to ease stress and, if needed, the same amount in the evening for better sleep. Effects are usually felt within 30 minutes and can last for 8-12 hours.

Green Tea Supplements