In general, vitamin C supplementation at recommended doses seems to be safe. However, higher doses (3,000–10,000 mg) may cause diarrhea.[1] One meta-analysis noted an increased risk of dental erosion with chewable vitamin C tablets.[2] A rare but noteworthy possibility of nephrotoxicity after high dose administration has also been observed,[3][4] but this is unlikely to occur with typical oral supplementation.
What are vitamin C’s main drawbacks?
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•Last Updated: May 16, 2025
Supplemental vitamin C at recommended doses is generally safe, but high doses (3,000–10,000 mg) may lead to diarrhea and an increased risk of dental erosion with chewable tablets. There is also a rare possibility of nephrotoxicity with high doses, although this is unlikely with typical oral supplementation.