theobromine + caffeine

**Theobromine + caffeine** is a *combination* of two methylxanthines commonly found together in cocoa and chocolate products but also used experimentally and occasionally in combination dietary supplements. Both are pharmacologically active small molecules with similar core mechanisms: they are **adenosine receptor antagonists** and **phosphodiesterase inhibitors**, resulting in stimulant effects, smooth muscle relaxation (including bronchodilation), and modulated cardiovascular parameters. Theobromine is a more potent cardiac stimulant and vasodilator, but less active than caffeine in the central nervous system and has a longer half-life. Caffeine is a well-characterized CNS stimulant with effects on alertness and blood pressure, while theobromine tends to increase heart rate but not blood pressure, and at higher doses may produce negative mood effects. Their combination is postulated to provide methylxanthine benefits with a somewhat different side effect profile than caffeine alone[1][2][3]. These substances are investigated and used primarily for their psychostimulant, diuretic, and cardiovascular effects.