Vitamin C administration guidelines:
Vitamin C has been shown to be beneficial for people with certain diseases or conditions. High intakes of vitamin C have been associated with decreased risk of heart disease, cancer, eye diseases, and neurological conditions. High dose vitamin C, with an upper tolerable level set at 2 grams daily, has been shown to be safe. Among healthy individuals, the recommended daily intake of vitamin C is 75 mg for women and 90 mg for men. (18)
Vitamin C and the USPSTF:
For the prevention of cancer or cardiovascular disease, according to the U.S. Preventive Services Task Force (USPSTF), there is insufficient evidence to recommend for or against the use of vitamins A, C, or E supplements or multivitamins with folic acid or antioxidant combinations for the prevention of cancer or cardiovascular disease. (19)