Research on vitaminC in the common cold has been divided into effects on prevention, duration, and severity. Oral intakes of more than 200 mg/day taken on a regular basis was not effective in prevention of the common cold. Restricting analysis to trials that used at least 1000 mg/day also saw no prevention benefit. However, taking a vitaminC supplement on a regular basis did reduce the average duration of the illness by 8% in adults and 14% in children, and also reduced the severity of colds. Vitamin C taken on a regular basis reduced the duration of severe symptoms but had no effect on the duration of mild symptoms. Therapeutic use, meaning that the vitamin was not started unless people started to feel the beginnings of a cold, had no effect on the duration or severity of the illness.
Research on vitaminC in the common cold has been divided into effects on prevention duration and severity Oral intakes of more than 200 mg/day taken on a regular basis was not effective in prevention of the common cold Restricting analysis to trials that used at least 1000 mg/day also saw no prevention benefit However taking a vitaminC supplement on a regular basis did reduce the average duration of the illness by 8% in adults and 14% in children and also reduced the severity of colds Vitamin C taken on a regular basis reduced the duration of severe symptoms but had no effect on the duration of mild symptoms Therapeutic use meaning that the vitamin was not started unless people started to feel the beginnings of a cold had no effect on the duration or severity of the illness