I used to take an energy daily vitamin and the Zinc in it used to keep me up at night so I had to cut back a bit.  I forget how much Zinc was in it.
		
		
	 
Know what you're taking red Bulls and five hour energy is pure sugar (and other bull shyt)  I love Red Bulls too but I hardly drink them anymore.
Like I said technically Spinach gives you more overall energy than anything but what people want is a quick boost like Caffene, Quick boots lead to quick crashes.  
I remember when we were in Iraq they sold these energy drinks called 
Rip It  We all drink them and gave them to the Iraqi's and I remember I thought they were making frog sounds but they were asking for Rip it's.  One day this dude drank ten as a bet then we had to go out on a mission. That coupled with the protein shake he took made him literally shyt is pants we were out there for more than 14 hours.