Is Excess Vitamin C Dangerous? Kidney Risks Revealed
Source: Can overdose of vitamin C cause kidney failure? Nausea, diarrhoea and kidney stone risks explained (2025-11-24)
Consuming high doses of vitamin C is often perceived as safe, but recent research highlights potential health risks, especially concerning kidney health. While vitamin C is water-soluble and excess amounts are typically expelled through urine, excessive intake can lead to serious complications. Overconsumption may cause nausea, diarrhea, and the formation of kidney stones due to the conversion of vitamin C into oxalate, which can accumulate in the kidneys. In severe cases, this can contribute to kidney failure, particularly in individuals with pre-existing kidney conditions or dehydration. Recent studies from 2025 reveal that up to 90% of adults worldwide still believe high-dose vitamin C is entirely safe, despite evidence suggesting otherwise. The global supplement market has seen a 15% increase in vitamin C sales over the past year, driven by immune-boosting trends. Experts warn that doses exceeding 2,000 mg daily—far above the recommended dietary allowance (90 mg for men and 75 mg for women)—should be taken only under medical supervision. Furthermore, new findings indicate that certain populations are at higher risk: people with a history of kidney stones, dehydration, or chronic kidney disease are more vulnerable to adverse effects. The risk of oxalate kidney stones increases significantly with high vitamin C intake, and these stones can cause severe pain, urinary obstruction, and potential kidney damage. In addition to kidney concerns, recent research emphasizes the importance of balanced supplementation. Excessive vitamin C can interfere with medical tests, cause gastrointestinal discomfort, and in rare cases, lead to hemolytic anemia in individuals with G6PD deficiency. The latest guidelines recommend that individuals consult healthcare professionals before starting high-dose vitamin C regimens, especially if they have underlying health issues. Emerging evidence from 2025 also suggests that natural sources of vitamin C, such as fruits and vegetables, provide a safer and more balanced intake compared to supplements. The World Health Organization now advocates for obtaining nutrients primarily through diet, reserving supplements for deficiency cases under medical advice. In conclusion, while vitamin C is essential for immune function and overall health, moderation is key. Overdose risks, particularly kidney-related complications, underscore the importance of adhering to recommended daily limits and consulting healthcare providers for personalized advice. As research continues to evolve, staying informed about safe supplement practices can help prevent serious health issues and promote long-term wellness.