You're asking and I am answering.
I am suffering from an awful Summer cold and have been taking two or three 1000 mg vitamin C supplements and drinking an EmergenC a day. Is there any danger in taking too much of the vitamin? Can I overdose on vitamin C?
—Sniffles and C
Summertime colds are the worst. Sorry to hear you are suffering. It sounds like you are determined to get rid of this cold, but I fear you are being overly aggressive with the vitamin C. I think this is a great question, and to hear my answer, just read more.
Eating more than 75 mg of vitamin C is easy to do and not likely to harm you. Since vitamin C is water soluble, meaning your body doesn't produce or store the nutrient so you need to eat it everyday, your body will flush out the excess. Taking mega doses of supplements, on the other hand, can have an adverse effect on your system. It can lead to nausea, diarrhea, kidney stones (because the kidneys filter waste from your blood) and inflammation of the stomach lining (gastritis). In extreme cases it can cause faintness, dizziness and fatigue. Definitely not the results you're looking for.
I hate to burst your proactive cold fighting bubble, but most research indicates that taking 200 mg or more of vitamin C a day after you're already sick does nothing to shorten the duration of a cold. You need to take the supplements daily with the possibility of shortening your cold by eight percent. The common cold generally lasts seven to ten days, and the best remedy is to drink extra liquids and get plenty of rest.
Hope you feel better soon.