Vitamin C Side Effects
Generic Name: ascorbic acid
Medically reviewed by Drugs.com. Last updated on Aug 3, 2020.
Note: This document contains side effect information about ascorbic acid. Some of the dosage forms listed on this page may not apply to the brand name Vitamin C.
For the Consumer
Applies to ascorbic acid: oral capsule, oral capsule extended release, oral liquid, oral powder, oral powder for solution, oral powder for suspension, oral solution, oral tablet, oral tablet chewable, oral tablet extended release, oral wafer
Other dosage forms:
Side effects requiring immediate medical attention
Along with its needed effects, ascorbic acid (the active ingredient contained in Vitamin C) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur while taking ascorbic acid:
Less common or rare- with high doses
- Side or lower back pain
Side effects not requiring immediate medical attention
Some side effects of ascorbic acid may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common or rare- with high doses
- dizziness or faintness (with the injection only)
- flushing or redness of skin
- increase in urination (mild)
- nausea or vomiting
- stomach cramps
For Healthcare Professionals
Applies to ascorbic acid: compounding powder, injectable solution, intravenous solution, oral capsule, oral gum, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating, oral tablet extended release
Hyperoxaluria appears to be dose-related.[Ref]
Migraine headache has been reported with a daily dose of 6 grams.
The manufacturer reports temporary dizziness and faintness may be associated with too rapid of a rate during intravenous administration.[Ref]
Conditional scurvy is reported to occur following excessive doses of ascorbic acid (the active ingredient contained in Vitamin C) over a prolonged period of time. The mechanism of action for this condition is thought to be that large doses of ascorbic acid condition the patient over time for rapid clearance of ascorbic acid resulting in scurvy. The plasma levels of ascorbic acid appear to remain within normal limits. The actual existence of conditional scurvy remains controversial.[Ref]
Other side effects have included flank pain in less than 1% of patients. Conditional scurvy has also been reported.[Ref]
Nausea, diarrhea, and abdominal cramps appears to be associated with doses exceeding 2 g per day, although there have been some reports with as little as 1 g per day.
Esophagitis appears to be associated with prolonged or increased contact of ascorbic acid tablets with the esophageal mucosa.[Ref]
Hematologic side effects have included hemolysis.[Ref]
The majority of hemolysis reports have been associated with patients who have concurrent glucose-6-phosphate dehydrogenase deficiency.[Ref]
Local side effects have included transient mild soreness at the site of injection.[Ref]
1. Levine M, Dhariwal KR, Welch RW, Wang Y, Park JB "Determination of optimal vitamin C requirements in humans." Am J Clin Nutr 62(6 Suppl) (1995): s1347-56
2. Hathcock JN "Vitamins and minerals: Efficacy and safety." Am J Clin Nutr 66 (1997): 427-37
3. "How much vitamin C do you need?" JAMA 281 (1999): 1460
4. "Product Information. Cemill (ascorbic acid)." Abbott Pharmaceutical, Abbott Park, IL.
Frequently asked questions
More about Vitamin C (ascorbic acid)
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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.