A 2014 review in Nutrition Reviews analyzed data from 11 studies and showed that participants reported both the feeling of alertness and feeling of calmness after the intake of caffeine and theanine and performed more accurately in cognitive tasks of identifying or searching objects. (encha.com)
Pheromone diffusers are often used by veterinarians in their clinics to induce a state of calmness in their patients. (petfriendlyhouse.com)