Plus the placebo effect which is the only reason you get instant energy from any kind of energy drink. Even pure liquid sucrose takes at least 30 minutes to digest (aside from a negligible amount that's digested in the mouth.
There's some interesting studies that show energy gain during a workout from just rinsing your mouth with an energy drink and not swallowing any.
At least 30 minutes, apparently. Any effect you feel before that is placebo.
Which shouldn't be read as "not real". The placebo effect means that actual physiological changes are happening in your body, they have just been initiated by your PNI system rather than the the substance.
Also it's fun how can they name something "energy drink" and then advertise no calories. Where do I get the energy then?