Oolong Tea Benefits & Side Effects

Oolong tea a semi-fermented tea leaf of Camellia sinensis manufactured mainly in China and Taiwan. In other words, we can say that oolong tea is an intermediate between green tea and black tea. It is a traditional Chinese tea with amazing health benefits including anticarcinogenic, antioxidants and antilipidemic activities. Due to its complex processing, oolong tea has a higher unit price than that of other tea. Oolong tea is also consumed by only 2% worldwide.

Main components of Oolong Tea

Like other traditional tea, oolong tea also contains caffeine and polyphenols. Besides these other components, mg/100 ml are as follows (1)


Compound Amount mg/100ml
Catechin (C) 1.65
Gallocatechin (GC) 6.68
Epigallocatechin (EGC) 16.14
Epicatechin (EC) 5.08
Epicatechin gallate (ECG) 5.73
Epigallocatechin gallate (EGCG)  25.73
Allocatchin gallat 1.85
Gallic acid 2.19
caffeine 23.51
Polymerized 33.65
Total Phenol 99.32

Besides this other component of oolong tea are Caffeine, Amino acids, and Protein

Health benefits of Oolong Tea

1. Weight loss

Oolong tea specially aged tea induce weight loss and reduce fat accumulation. In a study done on animal model suggests that oolong tea helps in reduction of the adipose tissue weight and adipocyte size (2). Therefore drinking oolong tea helps in reducing obesity.

2. Healthy Liver

Oolong tea also helps in lowering the lipid level in serum and liver thus is healthy for the liver. Thus plays an important role in lipid metabolism and protects the liver and energy metabolism (2).

3. Prevents cancer

Studies suggest that oolong tea have potential in preventing cancer. the compound epigallocatechin- 3- gallate present in oolong tea shows prevention of cancerous cell development (3).

4. Hypoglycemic effect

Another health benefits of oolong tea are its ability to reduce plasma glucose and fructosamine level. OOlong tea also increases insulin activity and decrease serum and liver lipid. thus drinking oolong tea helps in controlling diabetes and highly preferred for diabetic persons (4).

5. control cholesterol

Daily consumption of oolong tea helps in normalizing the cholesterol level by reducing the lipid peroxide and dismutase super activity level (5).

6. Increase antioxidant activity

Oolong tea consumption helps in decreasing oxidative stress and prevents DNA damage (6). Studies were done on athletes shows that oolong tea decreases the oxidative stress and lipid peroxidation level (5).

7. Prevents hypertension and atherosclerosis

Consumption of oolong tea helps in increasing the fat oxidation and metabolic rate of the body. Studies show that daily consumption of 120ml oolong tea helps in reducing hypertension in Taiwan (7).

5 Health benefits due to polyphenols present in Oolong tea

1. Lowers LDL cholesterol levels
2. Inhibits the abnormal blood clots
3. Reduction of platelet aggregation
4. Lipid regulation and inhibition of proliferation and migration of smooth muscle cells
5. Boost immune system

4 Health Benefits due to Caffeine

Oolong tea contains 13 to 40 mg/cup caffeine depending upon the steeping time from 1 to 5 minutes. Caffeine consumption for adults should be in between 120 mg per day or 1.73 mg/kg body weight per day.
Some of the positive effects of caffeine are
1. Caffeine helps in increasing the metabolic rate of the body.
2. Reduces the risk of Type-2 Diabetes.
3. Reduces cancer risk and liver disease.
4. Caffeine’s stimulation excite the brain and central nervous system

Side Effects of Oolong Tea

Side Effects of polyphenols are:

1. Defective RBC manufacture because of disturbed iron bioavailability resulting in anemia.
2. Interfere DNA repair by disturbing folate activity.
3. Other side effects are Intestinal gas, Nausea, Heartburn, Stomach ache, Dizziness, and Muscle pain

Side Effects of due to the presence of Caffeine

1. Insomnia
2. Dizziness, headache, and nervousness
3. Uneven heart rate
4. High blood pressure
5. Excessive urination thus loss of water and minerals (more than 225 mg/day) (8)
6. Releases acid in the stomach thus make stomach upset
7. Inhibits iron absorption, therefore, anemic people should avoid caffeine (8)
8. Too much caffeine may increase the risk of abortion (8)
9. Caffeine may affect certain medication.
10. Caffeine consumption (more than 740 mg/day) increase frequent urination resulting in calcium loss followed by bone deterioration


  1. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1541-4337.2008.00043.x
  2. https://dx.doi.org/10.3390%2Fnu10020187
  3. https://doi.org/10.1080/10408398.2017.1347556
  4. https://doi.org/10.1016/j.fshw.2015.10.002
  5. http://agris.fao.org/agris-search/search.do?recordID=US201301050011
  6. https://doi.org/10.1080/10408690390826464
  7. https://www.ncbi.nlm.nih.gov/pubmed/15277285
  8. http://www.caflib.com/en/images/harmful-effects-of%20caffeine.pdf


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    Tea Health Benefits & Side effects – foodthesis.com.
    I actually do have 2 questions for you if you do not mind.

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