A recent medical alert from Dr. Kunal Sood, an anesthesiologist and interventional pain specialist, warns that overconsumption of vitamin C supplements can lead to kidney stone formation and long-term renal damage, especially among men and those with impaired kidney function.

Speaking to Hindustan Times, Dr. Sood clarified that the popular belief that higher doses of vitamin C strengthen the immune system is misleading, stressing that excessive intake may harm the kidneys instead of helping immunity.

Vitamin C, or ascorbic acid, breaks down in the body into oxalate, which combines with calcium to form calcium oxalate crystals—the most common cause of kidney stones.

A large-scale study involving over 197,000 adults found that men who consumed more than 800 mg of vitamin C supplements daily were significantly more likely to develop kidney stones, particularly when exceeding 1,000 mg per day.

Dr. Sood emphasized that this risk is linked to synthetic supplements, not natural vitamin C found in foods like citrus fruits, strawberries, and bell peppers, which provide safe and adequate daily doses.

Metabolic research revealed that consuming 1–2 grams daily can raise urinary oxalate levels by 20–60%, even in healthy individuals.

He warned that high doses offer no added immune protection and may instead lead to elevated uric acid and mineral accumulation in the kidneys, increasing the likelihood of painful stones.

Dr. Sood concluded with this advice:

“Always use supplements under medical supervision. Stay well-hydrated, monitor urinary health, and maintain balanced calcium and sodium intake for optimal kidney protection.”