Oolong tea, or oōlióng(dé), is a type of traditional Chinese tea that’s popularly enjoyed in Asian countries. 

It’s rich in antioxidants and has been linked to several health benefits, such as lowering blood pressure levels and supporting brain health.

This article explores the health benefits of oolong tea as well as its safety and uses.  

Black, green, and oolong tea are considered the three major types of tea. 

Like green and black tea, oolong tea is made from the leaves of the Camellia sinensis plant. The differences between teas have to do with the level of oxidation to which the tea leaves have been exposed. Oxidation is a process that involves exposing tea leaves to air for them to dry and darken.

Oxidation impacts the color and flavor of tea. Green tea undergoes minimal oxidation, while black tea is fully oxidized. This is why black tea leaves have a deep brown color and a more intense tea flavor than green tea.

Oolong tea is partially oxidized, meaning it undergoes more oxidation than green tea but less than black tea. This results in a color and taste that lies somewhere between green and black tea.

Although oolong tea is often thought of as a single tea, there are many types of oolong tea, each with a different color and flavor. Some types of oolong tea undergo less oxidation and have a lighter flavor, while others have a more intense tea flavor due to longer oxidation times.  

Like green and black tea, oolong tea contains caffeine, with one cup providing 38.4 milligrams (mg) of caffeine. For comparison, the same serving of black and green tea provides 47.4 and 29.4 mg of caffeine, respectively.

Tea, including oolong tea, is a source of beneficial compounds, including catechins, which have antioxidant and anti-inflammatory effects in the body.  Drinking tea has been associated with several health benefits, such as improvements in heart and brain health.

Drinking oolong tea may help reduce heart disease risk factors such as high blood pressure and high blood lipid levels. 

Researchers think that tea, including oolong tea, helps lower blood pressure through several mechanisms, such as relaxing smooth muscle contraction, reducing blood vessel inflammation, inhibiting the activity of a blood vessel constricting enzyme called renin, and increasing the production of the blood vessel dilating molecule nitric oxide.

A 2023 study that included 76,673 Chinese adults between the ages of 30 and 79 found that those who consumed tea, including black, green, and oolong tea, had a 10% lower risk of high blood pressure.

Though studies investigating the effects of oolong tea on blood pressure are limited, an older study from 2004 that included 1,507 Chinese adults showed that those who drank at least a half-cup of moderate-strength green or oolong tea for one year were 46% less likely to develop high blood pressure compared to those who didn’t drink tea. For people who consumed two and a half or more cups of tea per day, the risk of high blood pressure was reduced by 65%, which suggests that regularly drinking oolong tea may be an effective way to protect heart health.

In addition to supporting healthy blood pressure levels, drinking green tea may also help lower blood lipid levels.

A 2014 study that included 3,041 Chinese adults, of which 1,651 were newly diagnosed with high lipid levels, found that the participants who consumed more than two and a half cups of oolong, green, or black tea per day had the lowest odds of having high blood lipid levels.

The researchers also found that the consumption of oolong tea for 21 years or longer was associated with 3.22, 6.69, and 11.99% lower blood levels of total cholesterol, LDL-cholesterol, and triglyceride levels, respectively.

The catechins found in oolong tea may help reduce blood lipid levels by inhibiting the activity of an enzyme called lipase, which helps decrease the intestinal absorption of fat. 

Oolong tea is an excellent source of antioxidant and anti-inflammatory compounds that help protect cells from oxidative damage, such as polyphenols like theaflavins, thearubigins, epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG).

Oolong tea is also rich in tea polysaccharides (TPS), which are carbohydrates that have been shown to have potent antioxidant activity.

Following a diet high in foods and drinks that contain antioxidant and anti-inflammatory compounds, like oolong tea, could help protect against certain health conditions, including a type of mouth cancer called oral squamous cell carcinoma (OSCC).

A 2022 study of 1,773 Chinese adults, including 744 people newly diagnosed with OSCC,  found that people who drank oolong tea had a 31% lower risk of developing OSCC than people who didn’t consume oolong tea. The study also found that those who drank over two cups of oolong tea had a 41% decrease in OSCC risk.

Oolong tea may also be protective against other types of cancer, including ovarian and nasopharyngeal cancer. However, research on the potential anticancer properties of oolong tea is limited, and more studies are needed to fully understand how drinking oolong tea may protect against certain cancers.

Drinking tea has been associated with several benefits for brain health. For example, tea intake has been linked with lower rates of depression and cognitive decline. 

A 2021 study that analyzed data on 13,115 older Chinese adults found that adults who drank fermented tea, including oolong tea, were up to 13% less likely to show depressive symptoms. The polyphenols found in oolong tea, such as EGCG, may help protect against depression by acting on certain pathways in the brain, such as the hypothalamic-pituitary-adrenal axis (HPA), the body’s main stress response system, and reducing inflammation and nerve cell damage in the brain.

These anti-inflammatory and neuroprotective properties may also help reduce the risk of cognitive decline. 

A 2022 study that included data on 1,545 older Chinese adults found that the participants who drank tea, including oolong tea, had a 40% lower rate of cognitive decline. The researchers suggested that drinking tea might help protect against memory decline by impacting a part of the brain involved in information processing called the posterior corpus callosum.

Though it’s rich in protective plant compounds, oolong tea isn’t a concentrated source of nutrients. That said, it does contain small amounts of minerals, such as potassium, magnesium, and phosphorus. 

One cup of oolong tea contains just 2.4 calories, making it a smart replacement for high-calorie beverages like sodas and sweet tea.

Replacing sugary and high-calorie beverages with zero or low-calorie beverages, like unsweetened oolong tea, is an easy and effective way to cut back on added sugar and excess calories. In fact, research shows that sweetened beverages, including soda and sweet tea, are the main source of added sugar in the average American diet.

Cutting back on added sugar by replacing sugary drinks with unsweetened oolong tea could help support healthy blood sugar levels, liver health, weight loss, and more. 

Drinking oolong tea is generally safe as long as it’s consumed in normal amounts. Like green and black tea, oolong tea contains caffeine, which is a stimulant, so it’s best consumed in moderation.

A cup of oolong tea contains 38.4 mg of caffeine, which is slightly more than the same serving of green tea and slightly less than the same serving of black tea.

People who are more sensitive to the effects of caffeine may experience symptoms like feeling anxious and jittery if they consume caffeinated beverages, especially in large amounts.

It’s recommended that adults keep their caffeine intake to less than 400 milligrams per day. In order to reach that limit, a person would have to consume more than 10 cups of oolong tea.

Oolong tea can be enjoyed as a lower-caffeine alternative to beverages that are more concentrated in caffeine, such as coffee, which provides around 96 mg of caffeine per cup. 

That said, although oolong tea is relatively low in caffeine, it shouldn’t be consumed too close to bedtime as it might interfere with your ability to fall and stay asleep, especially in those sensitive to caffeine. 

Oolong tea can be enjoyed the same way as other teas. Some people prefer to drink their oolong tea plain, while others prefer their tea with a squeeze of lemon and honey.

Oolong tea is usually steeped between one and five minutes. Shorter steeping times result in a lighter tea, while longer steeping times will create a tea with a richer taste.

Because oolong tea contains caffeine, it’s commonly enjoyed in the morning or afternoon, although those less sensitive to the effects of caffeine can drink oolong tea later in the day as well. 

Oolong tea isn’t as common in the U.S. as other teas, but it is sometimes sold in specialty tea and health food stores. You can also purchase oolong tea online. 

Oolong tea has a long shelf life. When properly stored in an airtight container at room temperature, loose-leaf tea and tea bags can last for up to two and three years, respectively.

Oolong tea is a type of tea that’s popularly consumed in Asian countries, like China. Its flavor and color fall somewhere between that of green and black tea, though there are many types of oolong tea to choose from, each with a distinctive taste.

Drinking oolong tea may benefit your health in several ways, as the protective compounds found in oolong tea may help lower blood pressure and lipid levels, and protect against cognitive decline and cellular damage. 

Oolong tea does contain a small amount of caffeine, so it’s best enjoyed in the morning or afternoon as a healthy, naturally sugar-free beverage.