Black tea comes from the fully oxidized leaves of *Camellia sinensis*. The process creates theaflavins and thearubigins, flavonoids that give the tea its dark color and bold taste. Most people drink it for the caffeine, which sharpens alertness and delivers a mild energy boost.
Claims about heart health are tied to those flavonoids, but the evidence beyond caffeine's basic effects is mixed. Enjoy it as a brewed beverage or take a standardized extract.
Watch your caffeine intake. Too much can lead to insomnia, jitters, or a racing heart. Drinking it with meals can also reduce how much iron your body absorbs.