I took what seemed like limitless amount of vitamin C a gram and a half every half hour for hours and hours until FINALLY bowel tolerance. I have found the benefits from vitamin C started showing up at least four days later and continued for a long time in different degrees (good days/bad days). I got an extremely healthy red glow in my cheeks and over the rest of my body, felt great. I now take a gram and a half a day maintanence with periodic bowel tolerances. I seem to get a horrible headache until after taking 10 or so grams with frequent urinating....Hope everything goes well for you.