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Moderate evidenceHeart & metabolic

Green Tea (brewed)

Brewed green tea is one of the better-supported everyday drinks: randomised trials show small falls in total and LDL cholesterol, and large cohorts link regular drinking with lower cardiovascular mortality. It does not meaningfully help weight loss, and the cup is safer than the concentrated extracts sold for that purpose.

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What the science says

  • Small improvements in cholesterol Moderate evidence

    A 2023 meta-analysis of 55 randomised trials found green tea lowered total cholesterol by about 7.6 mg/dL and LDL by about 5.8 mg/dL, with a small rise in HDL. The effects are consistent but modest, and many of the trials used green tea extract rather than brewed tea.

  • Lower cardiovascular and all-cause mortality Limited evidence

    In the Ohsaki cohort of 40,530 Japanese adults, women who drank 5 or more cups a day had about 23% lower all-cause mortality than those drinking less than 1 cup, with the strongest link for stroke; there was no link with cancer mortality. A dose-response meta-analysis of 39 cohort publications estimated about 4% lower cardiovascular mortality per extra daily cup, but rated the strength of evidence as low: tea drinkers differ from non-drinkers in many ways, so this is association, not proof.

  • Blood pressure Limited evidence

    The same 2023 meta-analysis found diastolic blood pressure fell by under 1 mmHg (0.87 mmHg) and no meaningful systolic change, an effect too small to matter for an individual.

  • Weight loss Limited evidence

    A Cochrane review of trials lasting at least 12 weeks found a pooled weight difference of 0.04 kg in studies outside Japan, which is effectively zero. Japanese trials reported larger losses but were too different from one another to pool.

Dosage & safety

Studied doseThe cohorts that link green tea with lower cardiovascular mortality describe 3 to 5 or more cups a day; a cup in these studies is about 236 mL. Brew about 2 g of leaf (one teaspoon or one bag) in water below boiling, around 70–80 °C, for 2–3 minutes. A cup usually contains about 20–45 mg of caffeine.
SafetySafe for most people as a drink. Tea taken with a meal reduces non-heme iron absorption: in a stable-isotope study, tea drunk with a porridge meal cut iron absorption by about 37% compared with water, and waiting 1 hour after the meal halved that loss, which matters if you are iron deficient. Green tea catechins sharply lower blood levels of the beta-blocker nadolol. Caffeine can disturb sleep; keep total caffeine under about 200 mg/day in pregnancy. Drinking tea at 60 °C or hotter was linked to a higher risk of oesophageal squamous cell carcinoma in a large cohort, so let it cool. The rare cases of liver injury involve concentrated green tea extracts, not the brewed drink.

How to take it

TimingMorning or early afternoon; the caffeine can disturb sleep if you drink it close to bedtime.
With food?Between meals is best if you need iron; with food is fine otherwise.
Worth knowingUse water below boiling (around 70–80 °C) and steep 2–3 minutes; boiling water and long steeping make it bitter. Let it cool before drinking.

Interactions

With medications

  • nadolol

    Green tea catechins block the intestinal transporter that carries nadolol and can sharply cut its blood levels. separate by several hours, or discuss another beta-blocker with your doctor

  • stimulant medication and high-dose caffeine products

    Additive caffeine effects: palpitations, anxiety and disturbed sleep. count green tea in your total daily caffeine

With other supplements

  • iron supplements and iron-rich meals

    Tea reduces non-heme iron absorption when taken at the same time. drink tea at least 1 hour after the meal or the supplement

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does green tea lower cholesterol?

Slightly. A meta-analysis of 55 randomised trials found green tea lowered LDL cholesterol by about 5.8 mg/dL and total cholesterol by about 7.6 mg/dL. That is real but modest (moderate evidence), and many trials used extract rather than brewed tea.

Does green tea help you lose weight?

Not meaningfully. A Cochrane review of trials lasting at least 12 weeks found a pooled weight difference of 0.04 kg outside Japan, effectively zero (limited evidence).

How many cups of green tea a day?

The cohorts linking green tea with lower cardiovascular mortality describe 3 to 5 or more cups a day. Brew about 2 g of leaf at around 70–80 °C for 2–3 minutes, and count its 20–45 mg of caffeine per cup.

Does green tea block iron absorption?

Yes. Tea drunk with a meal cut non-heme iron absorption by about 37% in a stable-isotope study, and waiting 1 hour after the meal halved that loss. If you are iron deficient, drink it between meals.

Scientific references

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