Guayusa

Guayusa yields xanthines such as caffeine. In addition to caffeine, guayusa also contains theobromine, commonly found in chocolate and L-theanine, a glutamic acid analog found in green tea to reduce physical and mental stress. Guayusa contains all of the essential amino acids for humans and has a "high antioxidant activity" Guarana is primarily used to boost energy. It has two times more caffeine than coffee beans.