What are vitamin C’s main drawbacks?

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.