Word of caution about ester C, its calcium based and most of us get plenty of calcium. Supplementing calcium usually leads to soft tissue calcification, especially since most people dont get the needed vit A, D and K to make sure the calcium ends up where its supposed to.
As to the dose, 2grams a day is hardly anything. 6g is the recommended minimum to stave off cardiovascular disease and thats in someone with low toxicity. Most adults can comfortably consume 12-20 grams per day without any digestive distress.
Another great natural remedy for constipation is magnesium. Most of us are deficient in it to begin with, athletes even more so. I personally consume 800-1200mg daily.