According to Mayo Clinic, typical caffeine levels are: Brewed coffee (8 oz): 96 mg Brewed black tea (8 oz): 47 mg Brewed green tea (8 oz): 28 mg https://www.m

According to Mayo Clinic, typical caffeine levels are: Brewed coffee (8 oz): 96 mg Brewed black tea (8 oz): 47 mg Brewed green tea (8 oz): 28 mg https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20049372 https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h... It's worth noting that tea also contains theanine, in addition to caffeine. Theanine binds to glutamate receptors and increases serotonin, dopamine, GABA, and glycine levels in various areas of the brain.