Theobromine

A mild xanthine alkaloid related to caffeine but with gentler stimulant effects and a longer half-life. Present in tea at about one-tenth the concentration of caffeine. Theobromine acts as a mild vasodilator and bronchodilator. Its name comes from Theobroma cacao (cocoa), its richest source, but tea is a meaningful secondary source. Theobromine contributes to tea's overall stimulant profile alongside caffeine and theophylline.

Mild vasodilation improving blood flow, bronchodilation supporting respiratory function, mild diuretic effect, mood elevation, may support dental remineralization.