There’s a lot of information floating around when it comes to caffeine levels in green tea compared to other drinks (like coffee). To start, it’s important to understand how caffeine affects the body. A naturally occurring compound found in somewhere around 60 varieties of plants (including coffee and tea), caffeine is a central nervous system stimulant that many people have come to rely on for energy: “[Caffeine] has been known to aid with attention and reactive time, as well as provide more energy, strength, and endurance for physical activities,” says Monica Auslander Moreno, a registered dietitian and nutrition consultant for RSP Nutrition. It’s also a gastric stimulant—which is why you may find yourself running to the bathroom after your morning cup of coffee—and a vasoconstrictor, which means it narrows the blood vessels and raises blood pressure.
“In susceptible individuals, [caffeine] may contribute to anxiety,” Moreno says, adding that the effects of caffeine may be beneficial and enjoyable for some people, and hard to tolerate for others. Maybe you’re someone who can’t fathom leaving your house in the morning before drinking coffee (hello, us), or perhaps you’re someone who feels anxious after just a small amount of coffee. Either way, the point is—caffeine affects everyone differently. Some people might metabolize caffeine very quickly, which makes them more tolerant of it, whereas others may be very sensitive.
Read on to learn whether green tea is a healthier source of caffeine than coffee, according to the experts.
How Much Caffeine Is In Green Tea?
An eight-ounce cup of green tea usually contains somewhere between 20 and 50 mg of caffeine, which is a fairly low dose of caffeine according to Jeanette Kimszal, a registered dietitian nutritionist based in New Jersey.
Keep in mind that not all green tea is the same—it comes in many varieties, including matcha, sencha, and bancha. The specific amount of caffeine in green tea will depend on the type of tea and how it’s brewed. Mia Syn, MS and RDN, says, "The most common type of green tea available is sencha green tea. Sencha green tea has a moderate amount of caffeine and is made through the most common processing methods in which the leaves are steamed and rolled."
“We've seen anywhere from 7 mg per gram to 84 mg per gram of caffeine in various types of green teas,” says Miriam Colman, former marketing specialist at Sugimoto Tea Company, which is a green tea company based in Shizuoka, Japan. Typically, matcha is the variety most likely to be high in caffeine, yet some matcha contains little caffeine.
“For non-matcha green teas, unless the green tea is roasted like hojicha, mixed with herbal ingredients, or cold-brewed, it's best to assume that a cup of green tea will have a noticeable amount of caffeine,” Colman says. If you want a smaller dose, according to Syn, bancha green tea often contains less caffeine than other types. "This is because bancha green teas use older leaves than sencha green tea."
Green Tea vs. Other Caffeinated Beverages
The amount of caffeine in coffee varies depending on the type of coffee bean, how the beans are roasted, and how the coffee is brewed. Typically, an eight-ounce cup of coffee has somewhere between 80 and 100 mg of caffeine (far surpassing green tea's typical range of 30 to 50 mg). But most people drink much more than eight ounces of coffee. At Starbucks, for example, a tall drink is 12-ounces, a grande is 16-ounces, and a venti is 20-ounces. Either way, most coffee contains more caffeine than green tea: "If you want a quick energy boost, coffee is a good option as it contains about twice as much caffeine as tea," notes Syn.
Green Tea: 7 to 84 mg of caffeine per eight-ounce serving
Coffee: 70 to 140 mg of caffeine per eight-ounce serving
Energy Drinks: 40 to 250 mg of caffeine per eight-ounce serving
Other drinks contain substantial amounts of caffeine as well. For example, energy drinks usually have somewhere between 40 and 250 mg of caffeine for an eight-ounce serving, and soft drinks contain around 30 to 40 mg of caffeine in a 12-ounce serving. This caffeine chart from the Center for Science in the Public Interest may be helpful if you’re curious how much caffeine is in some of your favorite drinks. "Tea is a good option if you want more sustained energy and attention levels, as green tea contains L-theanine, a chemical that metabolizes caffeine over a longer period," notes Syn.
How Much Caffeine Should You Have a Day?
Most healthy adults can safely consume up to 400 mg of caffeine each day, the U.S. Food and Drug Administration (FDA) says, while pregnant women should consume less than 200 mg per day.
Rather than deferring to broad guidelines that apply to everyone, Moreno explains that the amount of caffeine you take in each day should really depend on your tolerance and metabolism. If you’re feeling anxious or having trouble sleeping after consuming coffee, it may be wise to cut back a bit, whereas others can consume higher amounts of caffeine without problems. If you do decide to cut back, be sure to do so gradually to try to avoid headaches and other withdrawal symptoms. It’s also a good idea to speak with a physician if you have any questions or concerns about caffeine intake.
The Final Takeaway
Green tea may be a good alternative for people who are looking for a drink with a lower dose of caffeine per serving, Kimszal says. "Based on current research, everyone, including pregnant women, should not consume more than 300 mg of caffeine daily," adds Syn. But as mentioned, caffeine tolerance varies from person to person, and caffeine content varies from beverage to beverage, so the ideal source of caffeine won’t be the same for every individual.
While caffeine provides a boost of energy, it shouldn’t be the only thing you rely on to keep you going throughout the day, nutritionists say. As you reach for caffeine throughout the day, remind yourself that food can be an equally good (or better) source of energy than caffeinated drinks.
Cappelletti S, Piacentino D, Sani G, Aromatario M. Caffeine: cognitive and physical performance enhancer or psychoactive drug? Curr Neuropharmacol. 2015 Jan;13(1):71-88. doi: 10.2174/1570159X13666141210215655.
U.S. Food and Drug Administration. Spilling the beans: how much caffeine is too much? Updated December 12, 2018.