LivOn Laboratories

Your body can only absorb as much oral Vitamin C as your limited number of nutrient transporters can carry — from the digestive system to the bloodstream, and then from the bloodstream to the cells. 
The amount of non-liposome-encapsulated Vitamin C absorbed in the blood decreases dramatically as the dose size increases. Of a 20 mg dose, 19 mg (98%) can be absorbed. Of a 12,000 mg dose, only 16% (1,920 mg) is absorbed, with all that excess causing some major gastric distress when it leaves the body. 
Vitamin C is water-soluble, so your body can’t store any excess when it gets left behind in either the blood or the digestive system.