In this study rats were administered MSG which, in addition to damaging the liver and kidneys, also damages the thymus gland, which is important for your immune system. When rats were administered vitamin C, it counteracted the toxicity in the thymus gland. Now that’s great news except for the fact that the vitamin C was administered in extremely high doses. For an average person, it would involve taking 35 grams of vitamin C per day. I sincerely doubt anyone can ingest that high a quantity of vitamin C without some serious gastrointestinal issues, whether the vitamin C is buffered or not. So I would just consider adding vitamin C to the arsenal and not relying on it as your sole source of counteracting MSG.
 
Bratisl Lek Listy. 2009;110(4):205-9.