Oolong Tea Side Effects You Should Consider

Green tea has many varieties and this includes Oolong tea. With the many benefits these teas bring, they can also have a number of side effects you need to be aware, including some for Oolong tea.

Oolong tea is oftentimes called the “half-fermented” tea because during the production process the fresh leaves of the tea are fermented halfway only through the abundant enzymes of the leaves. Black tea, on the other hand, is fermented completely.

Like all other varieties of green tea, Oolong tea has the same caffeine and polyphenol content; however, it does not contain Vitamin C. Polyphenols are excellent antioxidants, which help combat free radicals. Despite the long list of health benefits, people could still experience side-effects, most of which are attributed to its caffeine components.

Caffeine Side Effects

If caffeine is taken in large amounts over a long span of time, including Oolong tea, people could experience dizziness, heart palpitations, irritability and insomnia. Caffeine overdose could result in diarrhea, vomiting, nausea, loss of appetite and headaches. According to the medical center of the University of Maryland, people who are experiencing vomiting or abdominal spasms after a tea drink may be having caffeine poisoning. Further, caffeine sensitivity could manifest through skin rashes and hives.

Drug Interactions

People must consult a health care professional before supplementing their daily eating regimen with Oolong tea, most especially when certain maintenance medications are taken-in. Those that are affected by drinking Oolong tea include phenylpropanolamine, oral contraceptives, weight loss medications, monoamine or lithium oxidase, ephedrine, clozapine, chemotherapy, aspirin and blood thinning products, metoprolol and propanolol, benzodiazepines, antibiotics, and adenosine.
Iron Metabolism: Oolong tea consumption could impair a person’s normal iron metabolism. When the body is iron deficient, anemia could result- a condition of low red blood cells in the body. Anemia causes fatigue and inability to perform activities of daily living as well as normal brain function.

Pregnancy Concerns

For nursing or pregnant women, Oolong tea intake should be minimized. Caffeine can cross the placenta and could affect the fetus. When large amounts are taken in, growth retardation or low birth weight may happen in some cases.

Medical History and Illnesses

People with anxiety-related issues, stomach ulcers, heart problems and kidney disorders must avoid drinking Oolong tea. Caffeine can disrupt the kidneys’ normal function through acting as a diuretic agent; hence, could worsen incontinence. Also, Oolong tea can speed up stomach acid production, which often times cause or worsen ulcer. Moreover, caffeine could increase heart rate and blood pressure.

Other Side Effects to Think About


A disorder characterized by low concentrations of serum potassium. This is a very common side effect because the excessive intake of caffeine affects potassium absorption; thereby, resulting in hypokalemia.


Oolong can interfere with the absorption of thiamine or vitamin B1. Therefore, excessive intake of the tea could result to thiamine deficiency or “beriberi”.

Stomach Upset

Tannin and caffeine, which are present in Oolong tea, could stimulate gastric acid production. This could be an issue with those who are experiencing stomach ulcer and heartburn. The gastric acid excess could rise up and move into the esophagus, which then causes irritation.


Oolong tea’s caffeine has the ability to increase eye pressure. This increase can happen in 3 minutes and could last 90 minutes.

Weak Bones

Oolong tea may flush out your body’s stored calcium through the urine. This, of course, could interfere with your normal bone growth and development. If you’ve been diagnosed with osteoporosis, limit yourself to only 3 cups each day. Calcium supplements could help in replenishing the flushed out calcium. When you’ve got hereditary conditions which could harm the manner by which your system processes Vitamin D, seek the advice of a medical professional before taking in Oolong tea.