Health Benefits of Oolong Tea

Medically Reviewed by Dany Paul Baby, MD on November 27, 2022
4 min read

Oolong tea is a traditional Chinese tea. It’s made from the same plant used in black and green teas, but the leaves are processed differently.

This tea-making process is called oxidation. Exposing the tea leaves to air causes them to ferment, and the length of time a tea maker allows the leaves to oxidize impacts the tea’s color, flavor, and to an extent, its nutritional content. 

Green tea is unoxidized, which helps it retain some plant-based antioxidants like catechins, which would be lost or converted during oxidation. Black tea is fully oxidized, giving it a deeper, richer flavor. This fermentation process also forms nutrients called theaflavins, powerful antioxidants unique to oxidized teas.

Oolong teas fall somewhere in between green and black tea. Products sold range from low to high levels of oxidation, and the color of the tea gets darker based on how long the leaves were left to ferment. Greener oolong teas tend to have a rich, earthy taste, while darker varieties offer a more roasted flavor. 

As a semi-oxidized tea, oolong tea contains a range of antioxidants, including many found in both green and black teas. Antioxidants are nutrients that protect our cells from damage caused by aging, our lifestyle, and the environment. Over time, this damage contributes to many chronic diseases.

All teas contain high levels of antioxidants that offer a range of health benefits. However, research shows that the nutrients in oolong tea have stronger antioxidant and antimutagenic effects than green or black varieties. 

Oolong tea’s powerful antioxidants and other nutrients may offer health benefits like:

Lower Risk of Diabetes

Research shows that the polyphenols in oolong tea lower blood sugar levels. They also reduce insulin resistance, a condition where the body doesn’t properly use sugars in the blood. High blood sugar and insulin resistance are both risk factors for diabetes and other health conditions like obesity.

Heart Health

Oolong tea’s polyphenols activate an enzyme that breaks down triglycerides, a type of fat in your blood. These triglycerides contribute to the thickening of artery walls, increasing the risk of stroke, heart attack, and other heart diseases. Research also shows oolong tea can also lower your cholesterol, which at high levels is another heart disease risk. 

Weight Management

Research suggests that oolong tea may decrease body fat and boost metabolism, reducing the risk of obesity and aiding weight loss. Studies show oolong tea stimulates fat burning and increases the number of calories your body burns by up to 3.4%. 

Cognitive Support

Oolong tea is high in an amino acid called L-theanine, which studies show has cognitive effects like improved brain activity, better sleep quality, and reduced stress and anxiety. In addition, oolong tea’s antioxidants have brain-protective properties that may help prevent neurodegenerative diseases, in which parts of the nervous system stop working. Scientists continue to study the tea’s potential in preventing diseases related to cognitive decline, like Alzheimer’s and dementia

Many of oolong tea’s health benefits are attributed to its antioxidants like polyphenols, but it also contains other health-boosting vitamins and minerals. Research shows that oolong tea’s fluoride content is comparable to what dentists recommend to prevent cavities. It may also reduce the risk of tooth loss and oral cancer.  

Oolong tea is also an excellent source of:

Nutrients per Serving 

One cup of brewed oolong tea (about 2 grams of tea leaves in eight ounces of water) contains:

Portion Sizes

Because oolong tea contains caffeine, drinking it in high amounts can have adverse side effects like headaches, irritability, increased heart rate, and insomnia. Experts recommend not exceeding 400 milligrams of caffeine a day, and one cup of oolong tea contains about 38 milligrams per serving.

Oolong tea is widely available where other teas are sold, and you can often find it on café and restaurant menus. It’s available in loose-leaf form or pre-packaged in tea bags. 

To make it at home, you want to use water that is just shy of boiling — around 190 degrees Fahrenheit or 90 degrees Celsius. This ensures the best flavor profile but also reduces nutrient loss. Higher water temperatures can destabilize and reduce the tea’s antioxidants like its polyphenols.

Researchers found that oolong tea has the strongest antioxidant activity when soaked at these temperatures for 3 minutes. You can also serve it iced by brewing it with hot water first and then allowing it to cool. 

To make the perfect cup:

  • Prepare about 2 tablespoons of loose-leaf tea or one tea bag.
  • Heat water to just shy of boiling.
  • Seep the tea for 3 minutes.
  • Test the tea for your preferred taste, but remove it within 10 minutes to preserve the antioxidant activity.