Yes, it is possible to overdose on vitamin C, especially when large amounts are taken as supplements. Although vitamin C is considered a low-toxicity vitamin, consuming very high doses can cause unpleasant symptoms. Problems are more likely when more than 2000 mg per day is taken from supplements.
The most common symptoms affect the digestive system. These may include diarrhea, nausea, vomiting, heartburn, and abdominal pain. Some people may also notice burning when urinating or an increase in urine volume. These symptoms happen because the body cannot absorb large amounts of vitamin C, so the excess remains in the digestive system or is eliminated in urine.
Taking very high doses over time may also increase the risk of kidney stones, especially in people who already have kidney problems or a predisposition to stones. Excess vitamin C can also increase iron absorption in the intestine, which may cause complications in people with conditions such as hereditary hemochromatosis, thalassemia, sickle cell anemia, or G6PD deficiency.
In most cases, a balanced diet that includes foods rich in vitamin C, like kiwi, strawberries, oranges, broccoli, and peppers provides you with enough of this nutrient. Supplements should only be used when recommended by a doctor or dietitian. If symptoms appear while taking vitamin C supplements, it is important to stop the supplement, drink water, and consult a healthcare professional.