Matcha Tea: Benefits, Preparation and What the Research Really Shows

A powder of ground green tea leaves on a stone mill, from the same plant as all teas, Camellia sinensis. Its distinctive feature lies in two things: the tea plants are covered for several weeks before harvest, and the entire leaf is consumed in suspension in water rather than being steeped and then discarded. So you consume everything the leaf contains, not just what passes into the water.

Because shading modifies the chemistry of the leaf. Deprived of direct light for three to four weeks, the tea plant slows its growth, produces more chlorophyll, which gives it a jade green color, and above all retains more theanine, the amino acid responsible for umami taste and the calming effect. In sunlight, some of this theanine is converted into catechins, which are more bitter. Shading is therefore what directs the leaf toward a profile rich in theanine.

No, and a Japanese trial published in Nutrients demonstrated this quite spectacularly. Researchers compared commercial matchas and found that the anti-stress effect only appears if the molar ratio between caffeine and EGCG on one side, and theanine and arginine on the other, remains below two. In other words, it's not just the quantity of theanine alone that matters but its balance with caffeine and catechins. Two green powders can have opposite effects.

Thirty-nine participants received either a matcha selected for its favorable ratio, or a placebo matcha from which no effect was expected. Anxiety, measured as a stress response, was significantly lower in the group receiving the test matcha than in the placebo group. The authors conclude that to predict the mental effect of a matcha, you must verify both its theanine quantity and the ratios of caffeine, EGCG, and arginine in relation to it.

A systematic review of 21 studies on green tea concludes that cognitive benefits are observed under the combined influence of caffeine and theanine, whereas separate administration of one or the other has a lesser impact. A crossover trial in 20 volunteers measured brain response to an attention task: the theanine and caffeine combination produced significantly greater amplitude than placebo, but also than theanine alone and caffeine alone. It's the synergy that works, not one of the two ingredients.

Two situations must be distinguished. In healthy people exposed to stress, a systematic review of nine trials concludes that an intake of 200 to 400 mg of theanine per day can help reduce stress and anxiety. However, in patients with a diagnosed anxiety disorder, a network meta-analysis of 29 trials involving twelve plants found no statistical superiority of theanine over placebo. Everyday stress and anxiety disorder are not the same target.

Matcha itself contains caffeine and is not an evening beverage. However, its characteristic amino acid has been studied in isolation: a double-blind crossover trial in 30 adults receiving 200 mg of L-theanine per day for four weeks measured improvements in sleep quality scores, particularly in sleep onset latency and sleep disturbances, as well as a decrease in anxiety scores. This concerns theanine taken alone, not a bowl of matcha consumed in the evening.

Less than one might think, and a critical review from 2022 states it clearly: randomized trials show that matcha reduces stress, slightly improves attention and memory, and has no effect on mood. Results on cognition are contradictory. Cardio-metabolic effects have only been studied in animals. Anticancer data are very limited and cellular. The authors conclude that evidence remains limited and firm conclusions cannot be drawn.

Yes. A double-blind randomized trial against placebo followed 61 elderly people living at home for 12 weeks, with 3 g of fresh matcha powder per day. In the sex-stratified analysis, a significant improvement in MoCA cognitive score was observed in women in the active group. The authors suggest a protective effect against cognitive decline in elderly women living at home, without generalizing beyond this.

A randomized trial had untrained men consume a drink containing 1.5 g of matcha twice daily for eight then twelve weeks of strength training. Maximum leg strength tended to progress more in the matcha group, subjective fatigue after exercise was lower from the first week, muscle mass increased more in the second trial, and salivary cortisol was lower. Changes in gut microbiota were also observed and correlated with strength progression.

A bowl prepared with approximately 1.5 g of powder generally provides between 40 and 70 mg of caffeine, compared to 80 to 100 mg for a cup of filtered coffee. A bowl of matcha thus practically contains less caffeine than coffee, even though the matcha content per dry weight is high: you simply consume a small amount. The difference felt is mainly due to the presence of theanine, which accompanies the caffeine.

Half a teaspoon, or approximately 1.5 g, in a wide bowl. One hundred milliliters of water at 80 degrees, never boiling. Pour the water over the powder, then whisk with a chasen bamboo whisk using a rapid M-shaped wrist motion, not circular, for about twenty seconds, until a fine foam forms. The matcha is consumed within minutes after preparation, as the powder is in suspension and will settle.

Because water that is too hot brings out the bitterness of the catechins and degrades the aromatic finesse linked to theanine. A matcha prepared at 100 degrees becomes astringent and loses what the shading took weeks to build. Eighty degrees is the usual benchmark, which corresponds to water that has cooled one to two minutes after boiling.

In the morning or early afternoon, like any caffeinated beverage. Caffeine has a half-life of approximately five hours in adults, which means a bowl consumed at 4 p.m. still has half its active caffeine at 9 p.m. Sensitive individuals do better by setting a time limit rather than counting bowls.

First, the color: a bright jade green signals controlled shading and high chlorophyll content, a dull or yellowish green signals the opposite. Then the taste: umami sweetness dominates over bitterness in a first-harvest matcha, while frank bitterness betrays later leaves or less shaded leaves. Origin and harvest grade must be displayed. These visible criteria are indicators of the theanine-to-caffeine ratio highlighted in trials.

It contains caffeine: people who are sensitive, those suffering from heart rhythm disorders, anxiety, or insomnia should moderate their consumption. Pregnant or breastfeeding women should seek advice, as caffeine intakes are limited during pregnancy. Green tea can also reduce the absorption of non-heme iron: it's better to drink it away from meals if your ferritin is low. In case of regular treatment, the question should be discussed with your pharmacist.