Mayo Clinic Health Library

Question

Too much vitamin C: Harmful?

Is it possible to take too much vitamin C?

Updated: 03-20-2012

Answer

Vitamin C (ascorbic acid) is an essential nutrient. Still, it's possible to have too much vitamin C.

Vitamin C is a water-soluble vitamin that supports normal growth and development. Vitamin C also helps your body absorb iron. Because your body doesn't produce or store vitamin C, it's important to include vitamin C in your diet. For most people, a large orange, 1 cup (about 165 grams) of sliced strawberries, chopped red pepper or broccoli provide enough vitamin C for the day. Any extra vitamin C will simply be flushed out of your body in your urine.

For adults, the recommended dietary reference intake for vitamin C is 65 to 90 milligrams (mg) a day, and the upper limit is 2,000 mg a day. Although too much dietary vitamin C is unlikely to be harmful, megadoses of vitamin C supplements may cause:

  • Diarrhea
  • Nausea
  • Vomiting
  • Heartburn
  • Abdominal bloating and cramps
  • Headache
  • Insomnia
  • Kidney stones

Remember, for most people, a healthy diet provides an adequate amount of vitamin C.

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