Drinking green tea may help slightly lower your blood pressure and reduce your risk of heart attack, heart disease, and stroke.
Green Tea May Lower Blood Pressure
A normal blood pressure is less than 120/80 millimeters of mercury (mmHg). If you have high blood pressure, lowering it by 5 mmHg can reduce the risk of stroke by 34% and heart disease by 21%.1
Evidence shows that green tea may help lower systolic and diastolic blood pressure.
- Systolic blood pressure is the top number on a blood pressure reading, which represents the pressure exerted on the arteries when the heart beats.
- Diastolic blood pressure is the bottom number on a blood pressure reading, which represents the pressure in the arteries between heartbeats.
For healthy people, research shows that green tea may lower blood pressure by these amounts:2
- Systolic blood pressure: –2.99 mmHg
- Diastolic blood pressure: –0.95 mmHg
Green tea may have a more significant effect on people with high blood pressure. Studies have shown reductions of:
- Systolic blood pressure: –4.81 mmHg
- Diastolic blood pressure: –0.98 mmHg
However, the research on how green tea affects blood pressure is inconsistent.45
How Does Green Tea Lower Blood Pressure
Scientists think green tea may lower blood pressure thanks to its catechin content. Catechins are antioxidant compounds, such as Epigallocatechin gallate (EGCG), found in plants.6
Green tea catechins may lower blood pressure by affecting the cardiovascular system in the following ways:
- Protect against oxidation
- Reduce inflammation in the veins and arteries
- Inhibit thrombogenesis (the formation of blood clots)
- Improve endothelial dysfunction (issues with the lining of blood vessels)
- Stimulate nitric oxide production and promote vasodilation (expansion of blood vessels)
How Fast Does Green Tea Lower Blood Pressure?
There is no specific timeframe for drinking green tea to lower blood pressure, but existing evidence suggests that the longer you drink it, the better your outcome.
- Three months: According to one review, drinking green tea lowered participants’ blood pressure after three months of consumption, and drinking green tea for even more extended periods led to more significant drops in blood pressure.3
- Three to 16 weeks: Another review covered periods of three to 16 weeks and found varying blood pressure reductions from green tea during this time, noting that longer-term studies are needed.6
- Four weeks: A shorter four-week study found a reduction in systolic blood pressure but not diastolic.4 Drinking green tea for longer than four weeks may have led to greater reductions.
How Much Should You Drink for Results?
Scientists haven’t identified an optimal dosage of green tea for blood pressure and other health benefits.6 However, various studies have observed results in people consuming one-half cup to over five cups per day.
In one study, participants who drank two cups or more of green tea for over 10 years had lower blood pressure and a reduced risk of cardiovascular death.
Does Decaf Green Tea Have the Same Effect?
Hypothetically, drinking decaffeinated green tea should have the same effect on blood pressure as drinking caffeinated green tea. However, no research has yet compared the two.
Green tea’s effects on blood pressure are likely due to catechins and not its caffeine content. Caffeine is associated with raising blood pressure.
Green tea naturally contains both catechins and caffeine. Still, scientists believe that the catechin content is relatively higher, and therefore, its effects on lowering blood pressure outweigh caffeine’s effects on raising blood pressure.6
One review compared caffeinated and decaffeinated green tea extract supplements and found no difference in blood pressure effects.6
Other Teas for High Blood Pressure
Other types of tea may also lower blood pressure. These include:
- Matcha: This type of green tea has the greatest concentration of catechins.7 Like other green teas, it may lower blood pressure, perhaps even more due to its catechin content.
- Black tea: This tea is made from the same plant as green tea (Camellia sinensis), but, unlike green tea, it is fermented. Research shows that black tea can also lower blood pressure, but to a lesser degree than green tea.3
- Hibiscus tea: Sometimes called sour tea, this herbal tea is made from steeping dried hibiscus flowers. Hibiscus tea has been shown to reduce blood pressure.8
Potential Side Effects of Green Tea
Some people may experience mild side effects from green tea due to its caffeine content.9 Drinking too much green tea may lead to the following symptoms:10
- Anxiety
- Difficulty falling or staying asleep
- Headache
- Heart palpitations
- High blood pressure
- Increased heart rate
- “Jittery” feeling
- Nausea and upset stomach
Who Should Avoid It
Green tea is safe to drink. However, as with any caffeinated beverage, people who are pregnant or breastfeeding should limit their intake.9
Green tea extracts, which are supplements or pills containing extremely high levels of green tea compounds, have more health risks than the green tea beverage.
Green tea extracts can interact with certain medications (including medications for high blood pressure) and even cause liver injury in rare cases.9 Talk to a healthcare provider before starting green tea supplements.
Key Takeaways
- Drinking green tea may lower your blood pressure, with more significant reductions for people with high blood pressure.
- Green tea contains antioxidant compounds called catechins, which have heart-protecting effects and may help relax blood vessels, leading to lower blood pressure.
Verywell Health
