G6PD and Renal insufficiency: These side effects include an increased risk of hemolytic anemia in patients with G6PD (Glucose-6-phosphate dehydrogenase) deficiency, potential renal failure, and the formation of kidney stones due to the acidification of urine caused by vitamin C. Additionally, the metabolism of vitamin C can result in the formation of oxalic acid, potentially leading to hyperoxaluria [37].