Like Yerba Mate, to which it is related, Guayusa has a long history of use as a stimulant and tonic by indigenous people. Guayusa is used primarily by the Kichwa people of Ecuador, who consume it in the early morning hours of each day as they awaken and discuss the dreams of the night and plans for the day.
Guayusa contains caffeine, which makes sense given its use for morning ritual, but it also contains healthy compounds like those found in green tea, and its use is similar to that plant, as well.
Although stimulating, Guayusa is also considered relaxing, and to be an herb that promotes lucid awareness in dreams. Like green tea, Guayusa contains L-theanine, an amino acid that promotes alpha waves in the brain. Alpha waves are associated with wakeful relaxation and tranquility with clarity, and offset and smooth out the stimulating effects of the caffeine.