People have consumed tea for medicinal benefits throughout human history. Green tea is one of the primary types, and reportedly contains one of the highest concentrations of powerful antioxidants called polyphenols. Green tea has been shown to help prevent atherosclerosis, high cholesterol, several types of cancer, diabetes and liver disease. Green tea extract takes the properties of green tea, condenses them and puts them into pill that delivers a higher, more powerful dose than drinking tea. Most extracts allow for doses that can be taken daily.

On the Other: Too Much Can Have Side Effects

Consuming too much green tea can have some negative side effects. This problem becomes worse when taking extracts that deliver a more potent dose. Many of the more serious warnings relate to caffeine, which green tea contains. Too much caffeine overstimulates the central nervous system and can create problems ranging from insomnia to toxic reactions. Also, tea contains tannin, which may contribute to iron deficiency, and is associated with impaired iron metabolism and microcytic anemia in infants. Exceeding dosage recommendations for extracts is not recommended.

Bottom Line

While green tea has been consumed for thousands of years and is purported to have many health benefits, the Mayo Clinic notes that scientific evidence is unclear on its benefits, with the exception of good evidence that it can clear genital warts. As a tea, it requires a great deal of consumption to get to a point where green tea could be dangerous, but more potent extracts elevate this risk. Therefore it is advisable to strictly follow dosage guidelines when taking green tea in extract form. Also, because caffeine is the main culprit in negative side effects of green tea, extract users can lower this risk by getting products that have less caffeine.

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