What is oolong tea?

Oolong tea is made from parts of the Camellia Sinensis, the same plant used to make black and green tea. Oolong tea is good for weight loss, bone strength and density, and brain function.
Oolong tea is made from parts of the Camellia Sinensis, the same plant used to make black and green tea. Oolong tea is good for weight loss, bone strength and density, and brain function.

Tea is the world’s second most popular drink after water. You may have heard of green tea and black tea, but oolong tea is another variety that’s gaining popularity. Oolong tea is a traditional Chinese tea made from Camellia sinensis leaves. It’s a partially oxidized tea that combines the characteristics of both green and black tea. More and more studies have shown that drinking oolong tea may lead to many health benefits, such as weight loss, improved brain function, and stronger bones. 

Oolong tea is made from parts of the Camellia Sinensis, the same plant used to make black and green tea. The difference between the three teas is in how they are processed. Green tea is made from leaves that have not been crushed and aged, exposing them to oxygen and resulting in oxidation. Black tea is made from leaves that are fully crushed and aged, so they undergo full oxidation, which causes the leaves to blacken. The process of making oolong tea lies somewhere in the middle. The leaves are slightly pressed and left in the sun to dry, allowing partial oxidation. The difference in the oxidation time is what gives the teas their different colors.

Like many other teas, oolong tea contains high concentrations of polyphenols, antioxidants that can neutralize free radicals and give the teas their aromas. This means that drinking oolong tea brings many health benefits, some backed by numerous studies. Oolong tea also contains small amounts of proteins, carbohydrates, amino acids, lipids, vitamins, and minerals

Oolong tea may help with weight loss

Drinking tea has always been thought to promote weight loss. Recent studies show that tea helps you better manage enzymes and antioxidant interactions with your gut microbiota, the collection of bacteria in your gastrointestinal (GI) tract. The gut microbiota plays a huge role in your overall health, and research suggests that your diet significantly affects it. 

An animal study showed that extracts from oolong tea helped increase fat oxidation. This means oolong tea drives weight loss by directly decreasing body fat. Oolong’s tea promotion of weight loss can also be attributed to its caffeine. When tested on high-fat diet-treated mice, caffeine was found to enhance lipolysis, breaking down fats and other lipids. The results suggest that oolong tea may be used to treat obesity and fatty liver caused by a diet high in fat.

Oolong tea also affects the bile acid metabolism, or BA metabolism, which is responsible for assisting good microbes throughout the GI journey and promoting gut health. Oolong tea alters BA metabolism and promotes potential probiotic bacteria to help with digestion and processing of foods.

It is important to note that while some studies have linked the antioxidant activities and caffeine in oolong tea to weight loss, it doesn’t necessarily mean that drinking a few cups of tea every day will directly lead to weight loss.

Oolong tea may improve brain function

In recent years, scientists have found that drinking tea may help maintain certain brain functions and possibly protect against cognitive decline caused by age. Tea drinking has positive effects on brain organization as it helps to enhance the brain’s structural connectivities. One study showed that higher quantities of tea drinking were associated with a lower risk of cognitive impairment and decline. This was especially true for people who drink oolong tea. More research is needed to tell whether drinking tea does lead to a significant enhancement in brain functions and connectivity.

Oolong tea is known to contain L-theanine, an amino acid that boosts attention and reduces anxiety. This is backed by a 2014 review that found that both caffeine and L-theanine increased alertness and attention within the first hour or two after drinking the tea. Other studies have found that L-theanine can help prevent cognitive diseases like Parkinson’s disease and Alzheimer’s disease.

Caffeine in oolong tea also helps to release norepinephrine and dopamine, neurotransmitters that regulate mood and emotion. This helps to improve mood, attention, and overall brain function. 

Oolong tea may help with bone density and strength

Oolong tea may promote stronger teeth and bones. Several studies have shown that tea drinking positively affects bone mineral density. Higher bone mineral density improves bone strength and helps lower the risk of bone fractures. Polyphenols in tea enhance the development of osteoblasts from blood cells. Osteoblasts are responsible for forming new bones. 

One study showed that people who drank tea every day for the past ten years had 2% higher overall bone mineral density. Another study focused on postmenopausal women in southern China showed that drinking oolong tea boosted bone mineral density. Subjects who drank 1 to 5 cups a day saw the most benefit. Drinking more than 5 cups of oolong tea daily did not increase bone density.


According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

Other benefits of oolong tea

Numerous studies have found possible associations between drinking oolong tea and other health benefits. 

Oolong tea may lower the risk of developing type 2 diabetes

Oolong tea is high in polyphenols, which have been linked to reducing the risk of diabetic complications. Studies have shown that black, green, and oolong tea can improve insulin resistance and activate the insulin signaling pathway.

Oolong tea may protect against certain cancers

Scientists believe that tea's antioxidants, or polyphenols, may help lower oxidative stress and decrease the presence of free radicals in your body that can lead to cancer. Tea polyphenols may also slow the rate at which cancerous cells grow.

One experiment studying the link between oolong tea drinking and oral cancer revealed that drinking oolong tea led to a decrease in the cells that cause oral cancer. This is especially true for those with poor oral hygiene and those with certain tea-drinking habits. Subjects that saw the most positive change were 30 years or older, drank over 500 mL of oolong tea per day for fewer than 20 years, and usually drank warm and moderately concentrated tea. 

Oolong tea may promote oral health

A small study showed that drinking 1.0 liters of oolong tea daily for eight weeks reduced bacterial diversity in the saliva, which may cause some oral diseases. These results suggest that sustained oolong tea consumption has potential oral health benefits. 

Oolong tea may relieve eczema

Both black tea and green tea extracts have been studied as potential treatments for skin irritations such as atopic dermatitis or eczema. Using these tea extracts was associated with significant improvement in eczema within the first few days of treatment and continued improvement in the days following.

Oolong tea may be used for cleaning

A clinical trial showed that oolong tea can be used to effectively clean colonoscopy lenses. The trial showed that the lens washed with oolong tea versus water provided a clearer image during colonoscopy. 

Risks and side effects

Oolong tea contains caffeine, so drinking too much may lead to side effects related to caffeine, such as anxiety, headaches, and irregular heartbeat. Caffeine may also raise the blood pressure level for some people. People who have hypertension, or high blood pressure, should be wary of serious side effects when drinking oolong tea. An incident with a 72-year old male with hypertension who also takes blood pressure medication showed that he had stroke attack-like symptoms immediately after drinking a cup of oolong tea. 

Polyphenols in oolong tea have many beneficial effects, but too much can cause them to act as pro-oxidants and increase oxidative stress, which is bad for your health. Oolong tea drinking may also significantly increase the risk of esophageal cancer.

Both the United States Department of Agriculture (USDA) and the European Food Safety Authority (EFSA) consider it safe to drink 400 mg of caffeine a day, which is equivalent to 6 to 10 cups of oolong tea, given that the average cup is 8 ounces (240 mL). However, people who are pregnant or have hypertension should be careful when drinking oolong tea and limit the amount of tea consumption. 


Oolong tea has been shown to have many health benefits, including the promotion of weight loss, improvements to cognitive abilities, and help with increasing overall bone mineral density. In addition, oolong tea has also been linked to better blood sugar management, protection against certain cancers, and effectiveness against certain skin irritations. More research will need to be done to gather more evidence of oolong tea’s numerous health benefits and to improve the validity of research results. It’s safe to say that more people will turn to oolong tea for its many health benefits, and its popularity will continue to increase. 


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Medically Reviewed on 8/26/2022

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