Adrenalin
Adrenalin was a substance produced by the adrenal gland during times of stress, (COMIC: Ripper's Curse) often resulting in a state of fear, but also greater physical capability. (TV: Oxygen) "Right now," the Twelfth Doctor told a young Rupert Pink, "your heart is beating so hard, I can feel it through your hands. There's so much blood and oxygen pumping through your brain, it's like rocket fuel. Right now, you could run faster and you could fight harder, you could jump higher than ever in your life. And you are so alert, it's like you can slow down time." (TV: Listen)
The Doctor sometimes purposely scared his companions, to encourage an upsurge in adrenalin, as "Fear keeps you fast. Fast is good." (TV: Oxygen) The Doctor considered the result of this, a state of fear, to be a superpower. (TV: Listen) Kai Tobias compared the Doctor to an adrenaline junkie who thrived on saving people, living on the edge when the stakes were high. (AUDIO: Phobos)
It was poisonous to Blood Bugs. (COMIC: City of the Damned)
Leechers fed by draining the minerals, pheromones, and stimulants including adrenaline from their prey's kidneys and adrenal gland. (COMIC: Ripper's Curse)
The Mire fed on adrenalin and testosterone. (TV: The Girl Who Died)
Through her Raxacoricofallapatorian sense of smell, Blon Fel-Fotch Passameer-Day Slitheen identified Rose Tyler as "a ripe youngster, all hormones and adrenalin." (TV: World War Three)
The Cybermen of a parallel Earth could detect adrenalin in humanoids. During preparations for the Battle of Canary Wharf, the Cyber-Leader ordered that the Tenth Doctor be spared cyber-conversion due to an increase in adrenalin suggesting that he had vital information on the Daleks who Cybermen had been violently confronted by. (TV: Doomsday)
Adrenalin gave Miríl the strength and speed needed to place himself between Raphael and a sea creature. (PROSE: Timewyrm: Apocalypse)
The newly regenerated Thirteenth Doctor credited a "bit of adrenaline" as being partly responsible for "knitt[ing] [her] brain back together." (TV: The Woman Who Fell to Earth)
