What it does
The NIH consumer sheet describes vitamin C as needed to make collagen and as an antioxidant. It also describes a role in immune function.
What research can and cannot say
The sheet is the place to read what trials of vitamin C supplements did and did not find. A labeled amount is not proof that a bottle changes a health outcome.
A vitamin C label does not show that the product changes immunity or skin. A cosmetic is a different product.
Forms and label reading
Supplements often list ascorbic acid or a mineral ascorbate. Read the amount per serving on the Supplement Facts panel.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Amount and upper limit
Recommended amount. The NIH sheet lists 90 mg a day for men and 75 mg a day for women. People who smoke are listed at 35 mg more than that. Cited sheet
Upper limit. The sheet lists 2,000 mg a day as the upper limit for adults. Cited sheet
Safety
The sheet says amounts above the upper limit can cause diarrhea and other stomach upset.
Food sources
The sheet names citrus fruit, other fruit, and vegetables as food sources.
