What Is Ascorbic Acid?
The NIH Office of Dietary Supplements lists a recommended vitamin C intake of 90 mg a day for adult men and 75 mg a day for adult women, and an upper limit of 2,000 mg a day for adults. It says vitamin C generally has low toxicity and high intakes do not cause serious adverse effects, but that high doses can lead to diarrhea, nausea, abdominal cramps and other gastrointestinal disturbances, and that concerns about kidney stones and excess iron absorption are not generally considered a risk in healthy individuals.
FDA regulations at 21 CFR 182.3013 say ascorbic acid is generally recognized as safe when used in accordance with good manufacturing practice. The FDA says benzene can form at very low levels, in parts per billion, in some beverages that contain both benzoate salts and ascorbic acid or erythorbic acid, a closely related isomer, and that exposure to heat and light can stimulate the formation of benzene in those beverages.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe NIH Office of Dietary Supplements lists a recommended vitamin C intake of 90 mg a day for adult men and 75 mg a day for adult women. NIH Office of Dietary Supplements ↗
- Government sourceThe NIH Office of Dietary Supplements lists the upper limit for vitamin C for adults as 2,000 mg a day. NIH Office of Dietary Supplements ↗
- Government sourceThe NIH Office of Dietary Supplements says high doses of vitamin C can cause diarrhea, nausea and abdominal cramps, though serious effects are not expected. NIH Office of Dietary Supplements ↗
- Regulatory filingFDA regulations at 21 CFR 182.3013 say ascorbic acid is generally recognized as safe when used in accordance with good manufacturing practice. US FDA, 21 CFR 182.3013 (eCFR) ↗
- Government sourceThe FDA says benzene can form at very low levels in some beverages containing both benzoate salts and ascorbic acid or erythorbic acid. US FDA ↗
- Government sourceThe FDA says heat and light can stimulate benzene formation in some beverages that contain benzoate salts and ascorbic acid. US FDA ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.