How much Vitamin C Should one take? How much is too much? First of all, the best form is Ester-C, which is a low acid, and highly assimmilated C. A maintenance dosage can be from 500-1000mg daily. And when you are fighting a cold or flu, then you can safely take up to 3000mg/day. You really can’t take too much C because your body will begin to excrete it when you are close to bowel tolerance.