Oolong tea represents only about 2% of the tea that is produced and consumed around the world, but it’s well worth discovering (1).
It combines the qualities of dark and green teas, giving it several purported health benefits.
For example, consuming oolong tea may aid in weight loss and reduce stress.
This article explains everything you need to know about oolong tea and its health benefits.
Oolong tea is a traditional Chinese tea.
It’s made from the leaves of the Camellia sinensis plant, the same plant used to make green tea and black tea. The difference is in how the tea is processed.
The process of oxidation is what creates green, dark, or oolong teas.
Green tea is produced from fresh tea leaves that have not undergone oxidation, a chemical reaction that begins when the leaves are exposed to the air and which is responsible for the color and taste of different types of tea. Black tea is created when leaves are fully crushed to enhance oxidation, and oolong is created when leaves are wilted in the sun and slightly bruised to create partial oxidation (1,
Oolong tea is a traditional Chinese tea made from the partially oxidized leaves of the Camellia sinensis plant.
Similar to black and green teas, oolong tea contains several vitamins, minerals, and helpful antioxidants.
A cup of brewed oolong tea contains small amounts of calcium, magnesium, and potassium. It also contains about 38 mg of caffeine. In comparison, a cup of green tea contains about 29g of caffeine (
Oolong tea also contains L-theanine, an amino acid shown to have positive effects on relaxation and cognitive performance (
In addition to caffeine, oolong tea contains vitamins, minerals, amino acids, and beneficial tea polyphenol antioxidants.
However, the specific effects of oolong tea are generally not as well researched as those of green or black tea.
Nevertheless, not every study agrees on oolong tea’s ability to help ward off or ease type 2 diabetes symptoms, with a 2011 study involving approximately 5,000 Japanese men concluding that consumption of the tea may be a predictor for the onset of the disease (
The polyphenol antioxidants in oolong tea may help maintain normal blood sugar levels and decrease the risk of developing type 2 diabetes. However, the evidence is mixed, and more research is needed.
Regularly consuming tea antioxidants may also improve heart health (
Several studies have also investigated oolong tea specifically.
One study of more than 76,000 Japanese adults observed that men who drank 8 ounces (240 mL) or more of oolong tea per day had a 61% lower heart disease risk (17).
What’s more, a study done in China reports that adults who drank 1 to 2 cups per day of either green or oolong tea “significantly” lowered their risk for a stroke (
One thing to remember is that oolong tea contains caffeine, which may possibly raise blood pressure, or hypertension, slightly in some people. However, there have been inconsistent results when it comes to studies looking at a link between blood pressure and caffeine, so more research is needed before any definitive conclusions can be made (
Furthermore, since the caffeine content in an 8-ounce (240 mL) cup is only about one-fourth of that found in the same amount of coffee, any negative effect regarding hypertension is likely to be quite small (
Oolong tea may help decrease the risk of heart disease, stroke, and high blood pressure in some people, but more research is needed.
Tea consumption and weight loss have long been tied together; and indeed, many studies illustrate a connection between the bioactive compounds in tea and weight loss or obesity prevention (
While it was long believed that the antioxidant activity from tea was solely responsible for its capabilities to decrease body fat, researchers are beginning to suggest that tea’s ability to enhance enzyme inhibition, and antioxidant interactions with gut microbiota specifically, may actually be what’s driving the weight loss capability (
Interestingly enough, it comes to oolong tea itself. A recent animal study showed that extracts from oolong actually did help to increase fat oxidation — meaning they helped decrease body fat directly.
However, when it comes to studies on humans, only one small, older study points to its ability to increase energy expenditure in adults, which is basically the number of calories a body burns while at rest, but not fat oxidation. Clearly, more research has to be done before conclusions can be made (
It’s important to note that just because the antioxidant activities, caffeine, and appetite inhibitive qualities of tea have been linked with weight loss in studies doesn’t necessarily mean that drinking a few cups of tea every day is the ticket to losing weight.
The combination of caffeine and polyphenols found in oolong tea may help increase specific enzyme inhibition and the number of calories burned each day. This could ultimately aid in weight loss.
In fact, several components of tea may benefit brain function.
For starters, caffeine can increase the release of norepinephrine and dopamine. These two brain messengers are thought to benefit mood, attention, and brain function (
Further research shows that theanine, an amino acid in tea, may also help boost attention and relieve anxiety. A 2014 review reports that tea containing both caffeine and theanine increased alertness and attention within the first 1 to 2 hours after consumption (
Few studies have looked specifically at oolong tea, but a study from 2008 found that a “high level” of tea consumption was associated with a lower risk of cognitive impairment and cognitive decline. This effect was particularly strong for regular black and oolong tea drinkers (
Another smaller study from 2010 linked regularly drinking green, black, or oolong tea to improved cognition, memory, executive function, and information processing speed in older Chinese adults (
The caffeine, antioxidant, and theanine content of teas (including oolong tea) may have beneficial effects on brain function and mood.
Tea polyphenols might also decrease the rate of cancer cell division (
Over the years, there have been many studies investigating the connection between tea consumption and the lowered risk of certain cancers, including lung, esophageal, pancreatic, liver, and colorectal cancers. While there does seem to be some evidence of a decreased cancer risk, many of the studies caution that the evidence is not always statistically significant (
Most research in this field has focused on the effects of green or black teas, with the biggest effects noted for the green variety.
Since oolong tea falls midway between green and black tea, similar benefits may be expected. However, more research is needed on oolong tea specifically.
Similar to green and black tea, oolong tea may have protective effects against cancer.
The antioxidants found in oolong tea may help keep your teeth and bones strong.
One study showed that people who drank black, green, or oolong tea daily over a 10-year period had 2% higher overall bone mineral density (
A higher bone mineral density could lower the risk of fractures. However, a direct link between oolong tea and fractures has not yet been investigated.
Finally, research has linked tea consumption to better dental health, including decreased plaque and gingivitis, which equals healthier teeth overall (47).
Oolong tea may help increase bone mineral density. It may also strengthen tooth enamel and reduce the formation of dental plaque.
Both black and green teas have been studied for their ability to help ease the symptoms of atopic dermatitis, otherwise known as eczema, and while results are promising, more research is needed to provide definitive results (
Similarly, one small study from 2001 looked at oolong tea’s ability to help manage eczema in 118 individuals with severe cases of eczema. They were asked to drink 33 ounces (1 liter) of oolong tea per day, in addition to maintaining their normal treatment.
After one month, there was “marked to moderate” improvement in their conditions, with signs of improvement noticeable as early as 1 to 2 weeks into the study.
What’s more, the improvement persisted and was still observed in 54% of the individuals 5 months later (
The age and scope of this study is important to keep in mind when considering results.
The polyphenol antioxidants in oolong tea may help relieve symptoms of eczema, and the improvements may last for a long time — but more research needs to be done.
Oolong tea has been consumed for centuries and is generally considered to be safe.
That being said, it does contain caffeine.
Additionally, consuming too many polyphenol antioxidants can make them act as pro-oxidants, which are not good for your health. Excess intake may occur from taking polyphenol supplements, but this is unlikely from simply drinking tea (
It’s also possible that the flavonoids in tea may upset iron homeostasis in the body, making iron absorption more difficult, but the amount of flavonoid consumption and exact mechanisms of this issue need more research (
Both the United States Department of Agriculture (USDA) and the European Food Safety Authority (EFSA) consider daily intakes of 400 mg of caffeine as safe. This is equivalent to 48–80 ounces of oolong tea (1.4–2.4 liters) per day (
Given that the average cup is 8 ounces (240 mL), you could drink a total of 6–10 cups of oolong tea per day without consuming too much caffeine.
Drinking up to 10 cups of oolong tea per day is generally considered to be safe for most people.
Oolong tea may not be as well known or as popular as green or black tea, but it has similar purported health benefits. These include benefits for heart, brain, bone, and dental health.
In addition, oolong tea may help decrease your risk for developing type 2 diabetes, aid in protecting you from certain types of cancer, and offer supportive benefits if you’re trying to lose weight.
It also has less caffeine per cup than coffee, making it a good solution for those who are caffeine sensitive.