This formula's own materials name these two ingredients specifically as the source of its natural caffeine content: Green Coffee Bean and Theobromine.
Green Coffee Bean is rich in chlorogenic acid and disclosed as containing natural caffeine; Theobromine is a cacao compound offering mild, natural stimulant support for concentration and memory, per this formula's own materials.
Rather than a vague "natural energy blend" claim, this formula's own materials name both stimulant-family compounds directly — worth reading that specificity as part of the broader stimulant-caution disclosure elsewhere in the materials.