L-Theanine
定义
A unique amino acid found almost exclusively in tea (Camellia sinensis) that promotes calm alertness by increasing alpha brain wave activity. It works synergistically with caffeine to enhance focus without the jitteriness of coffee.
详情
L-theanine (gamma-glutamylethylamide) is one of tea's most remarkable compounds, accounting for 1-3% of dry leaf weight. First isolated from gyokuro in 1949 by Japanese scientist Sakato, it crosses the blood-brain barrier within 30-45 minutes of consumption, where it modulates neurotransmitters: increasing GABA and dopamine while promoting alpha brain waves associated with relaxed concentration. This creates the paradox of tea: simultaneously calming and energizing. The L-theanine to caffeine ratio explains why different teas feel so different — shade-grown teas like gyokuro and matcha have exceptionally high L-theanine levels, producing a smooth, sustained alertness, while sun-grown teas have lower concentrations. Research suggests doses of 100-200 mg (equivalent to 3-5 cups of quality tea) improve attention, reduce stress-related cortisol, and enhance sleep quality without sedation. L-theanine also contributes significantly to tea's savory umami flavor, which is why high-theanine teas taste sweeter and more complex.