Comparative stimulant and diuretic actions of caffeine and theobromine in man

Human subiects ingested measured quantities of caffeine and theobromine, separately and together, at random. The double‐blind technique was used. Caffeine altered self‐estimates of sleep latency and sleep quality in a dose‐dependent fashion and increased overnight urinary sodium excretion. Theobromine in equivalent doses had no detectable effect on sleep parameters or on urine composition, nor did it interact significantly with caffeine when the two were ingested together. Theobromine is much weaker than caffeine or entirely inert in these situations.