Vitamin C Side Effects

Although most people do not experience problems while taking vitamin C, side effects could occur if you take too much. Side effects that are typically not dangerous but may indicate that you are taking too much vitamin C include fatigue, nausea, drowsiness, and insomnia. Some of the more serious vitamin C side effects may include kidney stones, teeth erosion, and a blood clot in the legs.

 

Does Vitamin C Cause Side Effects?

Vitamin C usually does not cause significant side effects for most people, especially when taken at normal dosages. However, vitamin C can sometimes cause serious side effects as well, especially when taken at higher dosages.
 

Bothersome Side Effects of Vitamin C

Some people may experience bothersome side effects of vitamin C. These side effects are not typically dangerous, although they may be signs that you are taking too much vitamin C (since these side effects are more common at higher doses). These bothersome vitamin C side effects may include:
 
  • Nausea
  • Vomiting
  • Irritation of the esophagus
  • Heartburn or indigestion
  • Intestinal cramps
  • Fatigue
  • Flushing (redness of the skin)
  • Headaches
  • Insomnia
  • Drowsiness
  • Diarrhea.
     
Some people may experience irritation or allergic reactions when vitamin C is applied to the skin.
 

Serious Vitamin C Side Effects

Even though it seems like a harmless nutrient, vitamin C can cause some serious side effects, especially if too much vitamin C is taken.
 These side effects, which should be reported to your healthcare provider, include:
 
  • A blood clot in the legs (deep-vein thrombosis, or DVT)
  • Kidney stones
  • Erosion of the teeth (from long-term use of chewable vitamin C tablets)
  • Worsening of sickle cell disease
  • Hemolysis (destruction of red blood cells) in people with glucose 6-phosphate dehydrogenase deficiency
  • Increased aluminum absorption into the body (which can be especially dangerous for people with kidney disease)
  • Signs of an allergic reaction, such as an unexplained rash, itching, hives, swelling of the mouth or throat, wheezing, or difficulty breathing.
     
(Vitamin C Side Effects Continued: Page 2)
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;