yes, I've done this and it scared me how much I would have to take because when I kept increasing the doze I still didn't get even near to the point of "loose stool" - I just thought that my body simply is so much used to vit C (I've been using it for forever-ever since I've read about it several years ago that it can actually treat cancer and some other serious diseases when taken in large amounts or admnistered via an IV) that I would have to swallow the whole bottle or what - it would not help me to get my bowels going...
Maybe my body built a high tolerance to vit C, taking Triphala too -many people say it helps them, for me it doesn't do the trick either. Or senna or cascara sagrada.
Perhaps there's some genetics involved here, I don't know, but it's a huge pain (literally..)