L-theanine B

«L-theanine» — evidence level B. Dosage: 100-200 mg of L-theanine per 100-200 mg of caffeine; the classic ratio is 1:1 or 2:1 in favor of caffeine. Alone - 200 mg. Source: PMID 21040626, permanent link to the source in the list below.

L-theanine is a tea amino acid structurally close to glutamate. It competes with glutamate for receptors and increases the activity of inhibitory processes in the brain, and also affects the levels of gamma-aminobutyric acid and dopamine. The practical result is relaxation without drowsiness and smoothing of excessive stimulation from caffeine: subjective nervousness decreases, tremor and palpitations are reduced, and focus is preserved.

L-theanine capsules; green tea contains it in small amounts, so a 200 mg dose requires a supplement. It is usually combined with caffeine in a 1:1 ratio

• In combination with caffeine it improves attention and increases subjective alertness
• Reduces nervousness, tremor and palpitations caused by caffeine
• Does not cause drowsiness during the day
• May improve sleep quality when taken in the evening

• It has no ergogenic effect on its own - without caffeine it does not improve sports performance
• Some studies were conducted on small samples, and the effect on cognitive tests is not always reproduced
• A reduction in blood pressure is possible in sensitive people
• Data on long-term use are limited

• With caffeine - the main scenario of use, it smooths the side effects of the stimulant
• With antihypertensive and sedative drugs - an effect on blood pressure and drowsiness
• With other stimulants - mutual influence on arousal

• Under 18 years: There are insufficient studies in children and adolescents; not recommended
• Pregnancy and lactation: Supplement use during pregnancy and lactation has not been studied; caffeine should be limited at the same time
• Hypotension - caution
• Taking antihypertensive and sedative drugs - consult a physician
• Individual intolerance to caffeine - do not use the combination

• The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness · Giesbrecht T, Rycroft JA, Rowson MJ · Nutritional neuroscience, 2010 · PMID 21040626
• International society of sports nutrition position stand: caffeine and exercise performance · Guest NS, VanDusseldorp TA, Nelson MT · Journal of the International Society of Sports Nutrition, 2021 · PMID 33388079

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