It can either be 5-10days depends.... And also that don't take it once 600mg-10000mg, drink per tablet 500mg per hour or more so that the kidney wont excrete the excess vitamin c it will remain in your body...
In How Many Days Miscarriage Possible By Vitamin C?
Vitamin C is a water soluble vitamin your body will only take as much as it needs and it excrete the waste.