Why Green Tea is a Glass of Calm

cup of hot green tea in an outdoor cafe

Green tea is a less processed version of black tea, and it offers a variety of health benefits. For one, it's richer in catechins, compounds with antioxidant and anti-inflammatory benefits, relative to its more processed cousin. Its benefits are not limited to antioxidant benefits either. Research suggests that drinking green tea may offer other health benefits. For example, drinking green tea has a modest lowering cholesterol benefit and may reduce the risk of heart disease and stroke. Some studies suggest it may also have anti-cancer benefits, although this needs more research.

Can Green Tea Improve Your Mood and Help You Feel Calmer?

Can green tea help you chill out? An 8-ounce cup (236.59 mL) contains around 40 milligrams of caffeine, about half the amount found in a standard cup of coffee. Drinking it may make you jittery at first if you're not accustomed to caffeine, but there is some evidence that green tea drinkers feel calmer, especially when you compare green tea to the activating effects of caffeinated coffee.

What makes green tea more calming than a cup of coffee? It contains an amino acid called L-theanine. The reason you feel chilled when you drink a cup of green tea has to do with the way theanine affects brain waves, the electrical activity within your brain.

When you're alert and focused on a task, beta waves predominate. At the other extreme are theta and delta waves, waves that take over during sleep or when you're in a deep state of relaxation, like a trance of meditative state. Another type of brain wave called alpha waves prevail when you're deeply relaxed but still alert. Think of alpha waves as providing a calm state of alertness.

Unlike caffeine, L-theanine is not a stimulant and has the benefit of promoting mental relaxation without drowsiness. Plus, in animal studies, L-theanine lowers blood pressure. In humans, there's also evidence that it can improve brain function and reaction time.

Theanine versus Caffeine

Remember, green tea also contains caffeine. Whether you feel calm depends on the ratio of L-theanine to caffeine in a cup of green tea. For calmness, you want a green tea that has a maximal quantity of theanine. You can get that by buying green tea grown in the shade. Tea leaves that grow in the shade produce more of this calming chemical. You can also maximize the calming effects of green tea by buying a decaf version. Fortunately, decaffeinating only removes the caffeine, not the theanine.

fresh tea leaves inside a bag, tea plantation harvest

An advantage of having both caffeine and L-theanine in your tea cup is caffeine boosts alertness while the theanine calms.This state of calm alertness can help you be more productive without feeling wired, like you feel after a cup of caffeinated coffee. Plus, your brain becomes desensitized to the caffeine if you drink it regularly and you won't feel as hyped up.

Other Health Benefits of Green Tea

Another benefit of drinking green tea: The catechins in green belong to a family of natural compounds called flavonoids. These substances give fruit, vegetables their bright colors. Plus, they have the added benefit of reducing inflammation and oxidative damage. Some studies link flavonoid antioxidants with lower rates of cardiovascular disease, cognitive decline and certain types of cancer. One caveat: If you drink decaf green tea, you may get fewer flavonoids than if you drink caffeinated tea. Fortunately, it doesn't affect the theanine content of green tea.

The Bottom Line

Not only can L-theanine in green tea boost your mood and give you a calm alertness, it has the added anti-inflammatory benefits. So, it's an all-around healthy beverage to sip in moderation. Don't negate some of the health benefits by adding a heaping spoonful of sugar. Enjoy it in its natural state and you'll appreciate it's naturally vegetal flavor and aroma. If you need to sweeten it, Stevia or monk fruit are natural sweeteners that won't cause a spike in blood sugar. Find solace and inner peace with a calming cup of green tea!


  1. Harvard Health Publishing. "Ask the doctor: Drinking green tea may lower health risks"
  2. Trends in Food Science & Technology. Volume 10, Issues 6-7, June 1999, Pages 199-204
  3. Psychology Today. "What You Need to Know About L-theanine"
  4. MedicalNewsToday.com. "Does L-theanine have health benefits?"

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About the Author

Dr. Kristie Leong

Kristie Leong M.D. is a family practitioner with a strong background and knowledge in the area of nutrition and lifestyle medicine. She graduated from Virginia Commonwealth University's School of Medicine in 1990 and writes about nutrition and its role in health and prevention.

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