Green tea, also known by its botanical name, Camellia sinensis, has many traditional health-related uses, although medical research has not confirmed the validity of many of the claims of supplement manufacturers 1. Promoters of green tea extract supplements claim it can help you lose weight, help your heart be healthier and heal wounds, among other things 1. If you need a diuretic to help control your blood pressure, talk with your physician about it before attempting to use green tea extract or other supplements 1. High blood pressure poses serious health problems that require a doctor’s intervention.

Diuretic Effects

The caffeine contained within green tea extract increases the amount of urine your body expels, MedlinePlus reports 1. This works as a diuretic in your body, similar to the way medications work. Because caffeine makes you produce more urine, you have less water in your body, especially in your bloodstream. Less blood reduces blood pressure.

Green Tea Benefits

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Green tea extract may help you lose weight, and it may help you become more alert 1. It provides these benefits, among others, largely because of its stimulating effect. Green tea extract contains caffeine, a stimulant of your central nervous system 1. This heightens your alertness and gives you more energy. Caffeine also helps you to lose weight, because it keeps you from eating more and keeps your metabolism higher so you burn more calories. Caffeine also constricts your blood vessels, especially in your brain, which means it can help fight migraine headache pain.

High Blood Pressure

High blood pressure can occur for several reasons. Your heart may start pumping harder, forcing more blood throughout your body. It may do this because of heart disease or because your arteries have become clogged with plaque, making the inside of the arteries smaller. To get the proper amount of blood flowing throughout your body, your heart may have to pump harder, pushing blood through at greater pressure. One way your doctor may treat this is to prescribe a diuretic medication that reduces the overall amount of water in your body. Diuretics force excess water out of your body through urination. With less blood flowing, your blood pressure decreases.

Green Tea Side Effects

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The same substance that serves as a diuretic and central nervous system stimulant in green tea extract, caffeine, can also produce some side effects, especially during your initial use of the supplement 13. Green tea extract can make it difficult for you to get to sleep or stay asleep 1. It can make you feel nervous or irritable. You may get a headache from green tea extract, MedlinePlus notes 1. It can also cause a short bout of diarrhea. Most of these side effects will end on their own once your body adjusts to the supplement. You can counteract the potential insomnia by taking green tea extract many hours before bedtime 1. If side effects persist, consult your medical practitioner.