Deep in the rainforests of South America grows a leaf that indigenous communities have relied on for centuries — for energy, for clarity, for endurance. It's called guayusa (gwhy-you-sah), and it's the heart of every can of Shrub Fuel.

Unlike synthetic caffeine or green tea extract, guayusa delivers its energy alongside naturally occurring antioxidants and a rare amino acid called theobromine — producing a clean, sustained lift without the jitters or the crash that defines most energy drinks.