Vitamin C is typically studied in human trials in clearly defined settings with measurable endpoints: pneumonia treatment in hospital, blood vitamin C levels in relation to recent respiratory infections, type 2 diabetes markers (HbA1c, blood pressure, blood lipids), iron deficiency anemia (plant-based iron with vs without vitamin C), skin outcomes after microneedling with an antioxidant serum, wound healing in diabetic foot surgery, and oxidative-stress markers after viral in