Does Green Tea Actually Lower Blood Pressure?

Green tea does lower blood pressure, but only a little, a drop so small you might never notice it on a home cuff. It works best as one small habit alongside diet, exercise and any prescribed medicine, not as a replacement for them. The bigger surprise for many people is that green tea can quietly weaken certain blood pressure pills.

How Much Green Tea Lowers Blood Pressure

Blood pressure is written as two numbers, measured in millimeters of mercury (mm Hg), which this article calls points. The top number is the pressure as your heart beats. The bottom number is the pressure between beats.

Across 13 trials with over 1,300 people, green tea lowered the top number by about 2 points and the bottom by about 2 points.¹ A separate pooling of 13 trials found nearly the same: about 2 points off the top number and about 1.7 off the bottom.² A larger pooling of 24 trials found a smaller effect, a little over 1 point off each number.³ An honest expectation is roughly 1 to 2 points, not 10.

Home readings naturally swing by more than 2 points from one minute to the next, so you are unlikely to see tea’s effect on a single cuff reading. Blood pressure pills typically lower the top number by around 10 points, far more than tea does.

The effect may be larger in people whose top number is 130 or higher.⁴ The benefit also showed up mainly in longer trials and in those that accounted for caffeine.⁵ Not every trial finds a benefit, though. In one 6-week trial of healthy men, green tea made no measurable difference.⁶ People with normal pressure, or who drink it only briefly, may see little or nothing.

The studies disagree partly because they aren’t alike. Trials used different amounts, from brewed cups to extract capsules, and some lasted weeks while others lasted months. A drop of a point or two is a small contribution that adds to other habits like eating less salt, moving more and losing weight.

Why Green Tea Affects Your Blood Vessels

Arteries are muscular tubes that tighten and loosen, which changes how much room the blood has to flow through. When they relax and widen, the heart meets less resistance, so pressure in the system falls a little. Tense or stiff vessels keep resistance high, which is one reason pressure stays elevated.

Tea seems to nudge vessels toward relaxing, and it does so quickly. Within about 30 minutes of drinking green tea, an artery’s ability to widen improved in healthy people, while caffeine alone did not do the same.⁷ Across trials, drinking tea improved artery widening by about 40% compared with not drinking it.⁸ One likely reason is that green tea’s main plant compound, EGCG, triggers vessel linings to release a gas that relaxes blood vessels.⁹

The benefit may depend on the whole drink. Brewed tea improved artery widening while an extract pill or pure EGCG with the same EGCG content did not.¹⁰

Lab work points to other possible effects. In test-tube studies, green tea blocks the same enzyme that some common pressure pills target, more strongly than oolong, white or black tea.¹¹ Green tea compounds can also soothe cell damage linked to high blood pressure in lab dishes.¹² But blocking an enzyme in a tube is not the same as doing it in the body.

Green Tea and Blood Pressure Medicines

The best-documented case is nadolol. In healthy volunteers, green tea sharply lowered how much of the beta-blocker nadolol reached the blood and blunted its pressure-lowering effect for 48 hours.¹³ Someone treating high blood pressure with nadolol could get less protection than their doctor expects.

Several other drugs are affected too. In most studies, green tea cut the amount of drug in the body by anywhere from 18% to 99%.¹⁴ Affected drugs include the pressure pills lisinopril and celiprolol, the heart drug digoxin, and the statins atorvastatin and rosuvastatin.¹⁵ If you take any of these, regular green tea is worth mentioning to your doctor or pharmacist.

The reason is absorption. Many drugs must pass through the gut wall to reach the blood, and some rely on carrier proteins in the gut lining to get across. Compounds in green tea can interfere with those carriers, so less of the drug gets in. With less drug in the blood, the pill does less of its job even though you took the full dose.

Taking the tea at a different time from the pill may help, since interactions seem worse when the two are taken together.¹⁶ Don’t stop your medicine on your own, and don’t suddenly start drinking a lot more tea without talking to someone first. Tell your pharmacist roughly how many cups you drink each day so they can judge whether it matters for your drug, and ask whether to separate tea and pill by a few hours. After any change in tea habits, watch your home readings and report a sustained rise to your doctor.

Does Caffeine Cancel Out the Benefit

Caffeine can briefly push blood pressure up. The rise fades as the caffeine wears off, so it matters mainly if you measure soon after a cup, and people who rarely have caffeine tend to notice it more than daily drinkers.

Green tea has some built-in counterweights. EGCG blocked caffeine’s rise in blood pressure and stress hormones in animal tests.¹⁷ Another tea compound may dampen the body’s stress response that drives pressure up.¹⁸

A cup of green tea usually has less caffeine than a cup of coffee, so the jolt is typically smaller. Sensitive people may still feel jittery or see a brief rise. If you check your pressure at home, measure before your tea or wait about 30 minutes afterward. Decaffeinated green tea is a reasonable choice if caffeine bothers you or you drink late.

Brewed Tea Versus Extract Pills

Green tea extract is a concentrated form of tea compounds sold as capsules or powders. A capsule packs many cups’ worth of those compounds into one dose, yet the blood pressure benefit appeared mainly with lower doses of tea compounds, not higher ones.¹⁹ More is not better here.

The extra concentration adds risk. Concentrated extracts taken in large single doses caused liver problems, while brewed tea and tea in food did not.²⁰ Taking 800 mg or more of EGCG a day from extract pills raised liver warning markers in blood tests.²¹ Health Canada concluded extracts may carry a rare, unpredictable risk of liver injury.²² Very rare liver injury has also been reported from ordinary brewed tea, likely an unusual personal reaction.²³ If you notice yellow skin, dark urine or belly pain, stop the extract pills and see a doctor.

If you do take extract pills, check how many milligrams of EGCG each capsule contains and multiply by the number you take in a day, to see whether you approach the 800 mg level. Avoid taking a large dose at once on an empty stomach. Supplements aren’t checked like medicines, so what is in the bottle can differ from the label. Tell your doctor and pharmacist about any extract, since it can also change how well your medicines are absorbed.

How to Drink Green Tea for Blood Pressure

Benefits showed mainly in longer trials,²⁴ so drink it daily for at least a couple of months before judging. A realistic pattern is two to four cups of brewed tea spread through the day, not a large amount at once. Brewing with hot but not boiling water keeps the flavor milder and less bitter.

Keep it plain, since added sugar works against your heart health. Keeping salt low and staying active matter far more for pressure than tea does, and your prescribed medicine should continue unchanged.

Your genes may shape your response. People with one version of a gene that clears tea compounds saw the top number drop about 6 points two hours after an extract, while those with another version saw no drop.²⁵

To see whether it helps you, measure at the same time each day, seated and rested, so readings are comparable. Average a week of readings before you start and another week after about two months of daily tea. A change of a point or two is within normal swings, so look for a consistent trend rather than a single reading. Share the log with your doctor, who can tell whether it is worth continuing.

Is Hibiscus or Black Tea Better

In a 6-week trial of healthy men, sour tea lowered the top number while green tea did not.²⁶ Sour tea is hibiscus tea, made from the flowers of a different plant, so it isn’t true tea, which comes from the tea plant. It has a tart, cranberry-like taste and naturally contains no caffeine, which suits evening drinkers. Hibiscus can have its own drug interactions, so check with a pharmacist.

Green tea has more human trials behind its small effect, so its benefit is better established. The hibiscus result comes from a single trial, so it is promising but not settled.