← All supplements
Limited evidenceGeneral health

Matcha Green Tea

Powdered whole green tea leaf, so you swallow the leaf rather than an infusion. It reliably delivers caffeine and L-theanine; the trials on cognition, mood and metabolism are small and their results are inconsistent.

Where to buy

View on iHerb

Ships to 180+ countries · welcome discount for new customers

Referral link — this site may earn a commission on purchases.

What the science says

  • Cognition in older adults Limited evidence

    A 12-month randomised trial in older adults with cognitive decline found improvement in social cognition and sleep quality but not in general cognitive scores, and an earlier randomised study in community-dwelling elderly found no clear cognitive benefit. The picture across trials is mixed.

  • Attention under mild stress Limited evidence

    Several small randomised placebo-controlled studies by one Japanese group reported that daily matcha helped maintain attention after a mild psychological stressor. Effects were small, measured on task batteries, and largely attributable to caffeine plus theanine.

  • Weight and metabolic effects of green tea catechins Moderate evidence

    A systematic review and meta-analysis of randomised trials found that green tea catechins add a small amount to weight loss achieved with exercise in people with overweight or obesity. The effect is real but of little practical size, and the trials used catechin doses higher than a cup of matcha provides.

Dosage & safety

Studied doseTrials used roughly 2–4 g of matcha powder per day (about one to two teaspoons), providing perhaps 40–80 mg of caffeine and 20–40 mg of L-theanine.
SafetyContains caffeine, so it can disturb sleep and worsen anxiety or palpitations. Because you consume the whole leaf, matcha delivers more lead and other leaf-bound contaminants than brewed tea; choose tested sources. Concentrated green tea extracts (not the powder itself) have been linked to rare liver injury. Green tea reduces non-heme iron absorption when taken with meals.

How to take it

TimingMorning or early afternoon; the caffeine can disturb sleep if taken within about six hours of bed.
With food?Drink it between meals rather than with iron-rich food or an iron supplement.
Worth knowingBecause you swallow the whole leaf rather than an infusion, matcha delivers whatever lead and contaminants the plant took up — buy from a source that publishes heavy metal testing.

Interactions

With medications

  • nadolol and some other beta-blockers

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

  • warfarin

    Whole-leaf matcha supplies meaningful vitamin K, which can lower INR. keep your intake constant rather than varying it, and tell your anticoagulation clinic

  • stimulant medication and high-dose caffeine products

    Additive caffeine effects: palpitations, anxiety and disturbed sleep. count matcha towards your total daily caffeine

With other supplements

  • iron supplements

    Tea catechins substantially reduce non-heme iron absorption when taken together. separate by at least 2 hours

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

Frequently asked questions

Does matcha improve focus and memory?

Evidence is limited and mixed: small trials found matcha green tea helped maintain attention under mild stress, largely explained by its caffeine and L-theanine, and trials in older adults found no clear improvement in general cognitive scores.

Does matcha help with weight loss?

Only slightly: a meta-analysis found green tea catechins add a small amount to exercise-driven weight loss (moderate evidence), but trials used catechin doses higher than a cup of matcha provides, so the practical effect is small.

How much caffeine is in matcha?

Trials used roughly 2–4 g of matcha powder per day, about one to two teaspoons, providing perhaps 40–80 mg of caffeine and 20–40 mg of L-theanine. Avoid matcha within about six hours of bed.

Does matcha interact with iron or medications?

Matcha's catechins substantially reduce non-heme iron absorption, so separate it from iron supplements by at least 2 hours, and they can sharply cut levels of the beta-blocker nadolol. Its vitamin K can also lower INR on warfarin, so keep intake constant.

Scientific references

Related in General health