User blog comment:Omega natsu2/Chapter 372: Breach, Predictions./@comment-33019320-20140219094024/@comment-7418318-20140220095757

I just read the same thing on the Naruto wikia, but that "information" must come from a databook or something.

In the manga itself it was never stated whether it is self-sustaining or not. The anime subtitles certainly made it sound as if Naruto needed to keep supplying power when he learned stage 3.

But what really makes me think that the databook is wrong is the fight against Kakuzu. There Naruto's first rasen-shuriken (second if you count the combo attack with Yamato) just vanished before he could hit Kakuzu. If it's fully self-sustaining, how could it just vanish?