Green tea, along with Oolong and Black tea, originates from the Camellia Sinensis plant. Despite their distinct flavors, they share the same caffeine content, which ranges from 2.5% to 4% per cup, approximately one-third of that found in coffee. Interestingly, it’s suggested that about 80% of the caffeine in tea remains unabsorbed by the human body. Thus, while the taste of Green, Oolong, and Black tea may vary, their caffeine levels remain consistent.