Quick answer
Women need 75 mg of vitamin C a day and men 90 mg, and people who smoke need 35 mg more. The adult upper limit is 2,000 mg. White blood cells are saturated at about 100 mg a day, and above 1 g a day less than half of what you take is absorbed.1,2,3
Key facts
- Pregnancy raises the recommended amount to 85 mg a day, and breastfeeding to 120 mg.2
- The 90 mg Daily Value printed on US labels matches the recommended amount for men.2
- Blood levels rise only a little once intake passes about 200 mg a day.2
- Upper limits for children start at 400 mg a day for ages 1 to 3.2
Recommended amounts by age and stage
| Life stage | Recommended | Upper limit |
|---|---|---|
| Children 1 to 3 | 15 mg | 400 mg |
| Children 4 to 8 | 25 mg | 650 mg |
| Children 9 to 13 | 45 mg | 1,200 mg |
| Teens 14 to 18 | 75 mg boys, 65 mg girls | 1,800 mg |
| Men | 90 mg | 2,000 mg |
| Women | 75 mg | 2,000 mg |
| Pregnancy | 85 mg, or 80 mg under 19 | 2,000 mg, or 1,800 mg under 19 |
| Breastfeeding | 120 mg, or 115 mg under 19 | 2,000 mg, or 1,800 mg under 19 |
People who smoke need 35 mg more vitamin C a day than people who do not, in part because smoke raises the amount the body uses.1,2
These amounts count everything you eat, drink and take. They were set from vitamin C's work in white blood cells, and they sit far above the roughly 10 mg a day it takes to stave off a serious shortage.2
How much of a dose the body absorbs
About 70% to 90% of vitamin C is absorbed at intakes of 30 to 180 mg a day. Above 1 g a day, less than half is absorbed, and the absorbed excess is passed in urine.2
In a controlled study, a single 200 mg dose of vitamin C was fully absorbed, while single doses of 500 mg or more were absorbed less completely and more of them was passed in urine.3
White blood cells are saturated at about 100 mg of vitamin C a day, and above about 200 mg a day blood levels rise only a little.2,3
Put together, these findings describe a ceiling. Somewhere between 100 and 200 mg a day, cells are full and blood levels level off, and taking more mainly raises what passes into urine.2,3
Where the 75 and 90 mg figures come from
Two NIH studies tracked dose closely. Healthy volunteers lived in hospital for months, first on a diet almost free of vitamin C and then on fixed daily doses from 30 to 2,500 mg, with blood, cells and urine measured at each step.3,4
The NIH researchers who ran these controlled studies proposed recommended amounts of 200 mg a day for men and 90 mg for young women. The official amounts remain 90 mg and 75 mg.2,3,4
In healthy young women kept on controlled diets, blood and circulating cells were saturated at 400 mg a day, and higher doses were passed in urine.4
The authors of the 1996 study concluded that daily amounts above 400 mg had no evident value.3
Reaching it from food
In the 2001 to 2002 national survey, average intakes from food and drink were about 105 mg a day for men and 84 mg for women.2
Three quarters of a cup of orange juice and half a cup of cooked broccoli together come to about 144 mg, more than either adult recommendation.2
Five varied servings of fruits and vegetables a day can provide more than 200 mg of vitamin C.2
What's in ours
What’s in ours
- Men's Multi: Vitamin C, 150 mg per serving, from the label
- Immune Support: Vitamin C, 180 mg per serving, from the label
The upper limit, and who should ask first
The upper limit for adults is 2,000 mg a day from food and supplements combined, including during pregnancy and breastfeeding. It is 1,800 mg for teens aged 14 to 18 and lower for children. It does not apply to people given vitamin C as medical treatment by a doctor.1,2
Questions people ask
Is 1,000 mg of vitamin C a day too much?
It is under the 2,000 mg adult upper limit, but well past the point where cells are full, and less than half of a daily total above 1 g is absorbed. In the NIH study, oxalate and urate in urine rose at 1,000 mg a day.2,3
See what we make
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Sources
- Office of Dietary Supplements, National Institutes of Health. Vitamin C: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
- National Institutes of Health, Office of Dietary Supplements. Vitamin C: Fact Sheet for Health Professionals. Updated July 31, 2025. Opened 2026-10-07.
- Levine M, Conry-Cantilena C, Wang Y, et al. Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance. Proc Natl Acad Sci U S A. 1996;93(8):3704-3709. Opened 2026-10-07.
- Levine M, Wang Y, Padayatty SJ, Morrow J. A new recommended dietary allowance of vitamin C for healthy young women. Proc Natl Acad Sci U S A. 2001;98(17):9842-9846. Opened 2026-10-07.
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Immune Function and Infectious Diseases: Fact Sheet for Health Professionals. Updated March 10, 2025. Opened 2026-10-07.
- Adderall XR (mixed salts of a single-entity amphetamine product) extended-release capsules: prescribing information (Takeda Pharmaceuticals America). DailyMed, U.S. National Library of Medicine. Published May 6, 2026. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.