POPULAR BUT DANGEROUS: What to expect from Vitamin C overdosage.

Vitamin C also known as ascorbic acid is known for its numerous benefits and is very popular among old and young. It occurs naturally in some fruits and in synthetic form, is available in chewable tablets and syrups for use as a supplement.

Little wonder that it readily comes to mind when cold and flu strike, since it supports immune function and is an antioxidant (protects the body from damage by free radicals). True, taking Vitamin C after a cold begins can help reduce cold symptoms and duration.

However, some mistakenly assume that because it is water-soluble (excess amounts are excreted and do not accumulate in the body), it is harmless even when consumed in large doses. But this is hardly true.

There are problems that could result from taking more than the recommended dose of vitamin C, if you are not deficient. They include:

  • gastrointestinal symptoms like diarrhoea, heartburn, vomiting, bloating, indigestion and nausea
  • headache, foot cramps, muscle pain, face rashes, facial itching and flushing.
  • insomnia (cannot sleep well and has poor sleep)
  • tooth decay
  • anaemia (happens due to vitamin B12 deficiency – ingested large doses of synthetic Vitamin C interfere with synthetic B12 absorption when taken together)
  • kidney stones: excess vitamin c intake can cause deposition and collection of calcium oxalate leading to the formation of kidney stones in patients who have the tendency to develop it. Kidney failure can also occur in patients with a history of kidney disorders.
  • For those with a condition called hemochromatosis, vitamin C toxicity gives rise to iron toxicity  which cause damage to body tissues. This can lead to liver and heart disease. It should however be noted that this is not a concern for healthy individuals.
  • Too much vitamin C can skew a urine test.
  • Overdosage of vitamin C during pregnancy can cause a miscarriage.


  1. The possibility  and degree of overdosage varies according to the individual.
  2. It is seen mostly in prolonged overdose with synthetic vitamin C.
  3. Some effects from overdosage get cleared when the excess vitamin c leaves the system.
  4. The tolerable upper intake levels for vitamin C is 2,000mg (this does not apply to individuals receiving vitamin C for medical treatment).


One of many researches that support dangerous consequence of prolonged overdosage with Vitamin c is:

Taylor EN, Stampfer MJ, Curhan GC. Dietary factors and the risk of incident kidney stones in men: new insights after 14 years of follow-up. J Am  Soc Neprol 2004;15:3225-32.


See also:



What are Over-the-Counter Medications?

Recently Expired Drugs- Are They Still Safe to Take?

4 thoughts on “POPULAR BUT DANGEROUS: What to expect from Vitamin C overdosage.

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