I am not a big proponent of store bought drinks and juices. Most are jammed with WAY too much sugar. The so called "juice" drinks are also pasturized which ruins any health benefit because it destroys natural nutrients.
I found a brand of Kombucha called "Synergy" which knocks my socks off. Kombucha is a cultered (fermented) Chinese tea. This stuff also has L-theanine, probiotics and some B vitamins.
Low sugar (8g in 16oz)and certified organic.
I found it in my local Whole Foods Market for about $3 a bottle.
This is a free endorsement- I don't sell the stuff or make a penny if you buy any of it. But, I swear I get a boost whenever I drink it. Must work well with the Ortho-Mind and GeroNova R-Lipoic I use :-)