Green Tea vs. Black Tea: Caffeine, Health Benefits & When To Sip Each

This article breaks down the differences between green and black tea, including their caffeine content and potential benefits, to see which one's the best for health.

Black tea has a rich, malty flavor and is often enjoyed with a splash of milk or cream. Black tea can be purchased in tea bags or in loose leaf form, and is also found in tea blends, like chai tea.

The caffeine content of black tea varies, but research suggests it contains around 47 mg per cup2. For comparison, a cup of brewed coffee3 contains 91.8 mg of caffeine.

There are a variety of black teas to choose from, including:

Black tea can also be combined with ingredients like essential oils to create tea blends with different flavors. The popular Earl Grey tea is made by blending black tea with bergamot oil, for example.

Study findings suggest that regularly drinking antioxidant-rich black tea may help reduce the risk of several health conditions, including depression5, breast cancer6, and type 2 diabetes7. 

Black tea contains multiple compounds, including polyphenols and the amino acid L-theanine, that may reduce depression risk by modulating the activity of the neurotransmitter dopamine8 and the gut-brain axis—a signaling pathway between the digestive tract and the central nervous system. 

Research also suggests that drinking black tea may help decrease blood lipid levels, including LDL cholesterol, 9and may help encourage a healthy body weight by promoting lipid metabolism and inhibiting lipid absorption and accumulation10. 

Like black tea, green tea can be purchased in tea bags and as loose-leaf tea. You can also find it in powdered form as matcha tea. Green tea is usually enjoyed plain, but some people use lemon juice or sweeteners, like honey, to enhance the tea's flavor. 

A cup of brewed green tea12 contains only 29.4 mg of caffeine, which is significantly less than black tea. Since it's low in caffeine, people who are sensitive to caffeine's stimulatory effects can enjoy green tea without experiencing side effects like jitteriness and trouble falling asleep. 

There are several types of green tea, each grown in different ways and harvested during different seasons. They include:

Matcha is a type of concentrated green tea powder that's a rich source of antioxidants like flavonoids, flavonols, and phenolic acids, which compose up to 30% of its dry mass14. Matcha has become quite popular in the U.S. over the last decade and is commonly enjoyed in hot beverages like matcha lattes and in iced drinks.

Decades of research findings suggest that diets high in green tea can protect against several chronic diseases and health conditions, including certain cancers17, heart disease18, and high blood pressure19. 

Additionally, drinking green tea may help reduce adrenal hormone levels22 associated with stress. A small study found that drinking six cups of decaffeinated green tea per day for six weeks helped reduce the depression, anxiety, and stress associated 22with stuttering and significantly reduced elevated levels of the adrenal stress hormones cortisol, DHEA, ACTH, and corticosterone in teens with moderate stuttering.

That's because green tea contains higher levels of certain protective plant compounds than black tea, including EGCG and L-theanine, and may have more powerful disease-fighting properties. (Hence why it was named the best tea for overall health in mindbodygreen's power ranking.)

Studies also show that drinking green tea, but not black tea, significantly reduces the risk of cognitive disorders24 in some populations. Researchers suspect that its high level of catechins gives green tea an edge when it comes to its brain-protective effects. Green tea also contains a small amount of vitamin C, which has cognitive health-enhancing and neuroprotective properties25.

Also, remember that no one food or beverage will significantly impact your health alone. Your diet as a whole is what matters most when it comes to promoting optimal physical and mental health and reducing disease risk. Green and black tea can offer benefits, but they can't make up for an unhealthy diet.

If you're wondering which tea you should choose, it really comes down to your flavor preferences and caffeine tolerance. Here's a bit more info to help you decide on a tea that best suits your needs.

However, people looking for a more mellow way to start their day, or those sensitive to caffeine, may want to opt for green tea. Green tea is higher in L-theanine26, an amino acid that has calming and mood-boosting effects on the body, than black tea.

Green tea and black tea are caffeinated, so they're not the best choice to drink in the evening, especially if you're sensitive to caffeine. Instead of sipping on caffeinated tea before bed, you can enjoy a cup of decaf green or black tea or a naturally caffeine-free herbal tea like chamomile, which has sleep-promoting properties27.

Just make sure to wait a few minutes after brewing to enjoy your tea, as studies have linked regular intake of drinks above 140℉ with an increased risk of esophageal cancer30.

"Green tea contains less caffeine than black tea and it may have more antioxidant effects as well," says Manaker.

Sipping on a cup of matcha may help you wind down when you're feeling stressed. Matcha offers more stress-relieving benefits than regular green tea because matcha contains two times more of the stress-relieving amino acid L-theanine31 than regular green tea on average.

When shopping for green or black tea, you should keep a few things in mind:

First, consider your taste preferences. Remember, there are different types of green and black tea, each with a different flavor. For example, you might prefer matcha or bancha green tea if you like stronger-flavored green tea. Black tea drinkers looking for a lighter, less malty-flavored black tea may want to try Darjeeling tea, which is thin-bodied with fruity and floral flavor notes.

Another factor to consider is cost. Some teas, like high-quality matcha and certain types of black tea, can be very pricey, so it's essential to shop around until you find a tea that fits your budget. To save money, you can purchase tea in larger quantities as bulk items are usually sold at a discount. When stored properly, loose-leaf tea can last in your pantry for up to two years, and tea bags can last up to three years. 

Also, whether you're buying green or black tea, it's important to purchase products from reputable companies and opt for organically grown tea whenever possible. Purchasing organic tea ensures that the tea is grown without the use of synthetic pesticides and herbicides32.

Lastly, when purchasing tea in bags, steer clear of tea bags made with nylon, such as "silken" tea bags. These bags can leave behind microplastics33 in your tea, which can build up in your system over time and potentially harm your health. For a safer way to brew tea, consider investing in a steeper made of nontoxic material, like stainless steel.

Green and black tea both offer several benefits, from providing health-promoting antioxidants to protecting against common health conditions. Although green and black tea can both be enjoyed as part of a healthy diet, green tea offers more benefits when it comes to antioxidant content and its positive effects on metabolic health and cognition.