3 xanthines
Caffeine
Caffeine is the bitter plant chemical that makes coffee, tea and cocoa wake you up, and plants make it partly to steer bees. Here is what 29 studies show for alertness, exercise, sleep, heart rhythm and pregnancy, which foods have it, and how much is safe.
Theobromine
Theobromine is the main methylxanthine in cocoa, and your body also makes some from the caffeine in coffee. Here is what 24 studies show for cholesterol, mood and cough, which foods have it, and why it is toxic to dogs and cats.
Theophylline
Theophylline is a trace compound in tea and also a prescription drug for asthma and COPD. Here is what 24 studies show about the drug, how little a cup of tea holds, and why doctors check blood levels.
