I tried it for a short while when I was at uni thinking it would answer all my running prayers. I can't remember for the life of me what the dosage was, or when it was taken... but to be honest I didn't feel any benefit from it at at least nothing noticeable.
Though I think it's more likely to have an effect with 'explosive' exercise (sprints, weights etc)
To aid running, the only things I can realistically see being of any use are 'carbo loading' products when you're doing very high mileages... and recovery drinks.
The extent to which they'll help is pretty hard to guage to be honest. I've tried a number of recovery drinks and not found them to make a huge difference. In fact my biggest gains in performance have come purely from increasing mileage and spending time stretching after hard or long sessions.