Vitamin C
It is a water-soluble antioxidant and is needed to make collagen. The bigger the dose, the lower the share absorbed; the excess leaves in urine.
Full ranking Dose tool Products (8,730)
Key facts
Sources: https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/ · FDA DV 90 mg (https://www.fda.gov/food/nutrition-facts-label/daily-value-nutrition-and-supplement-facts-labels); pre-2016 DV [60] (https://www.federalregister.gov/documents/2016/05/27/2016-11867/food-labeling-revision-of-the-nutrition-and-supplement-facts-labels); adult UL 2000 mg
How it works: What happens if you take a lot of vitamin C?
- At moderate intakes 70–90% is absorbed; above 1 g per day absorption falls below 50%.
- Vitamin C is an antioxidant and is needed to make collagen, L-carnitine and some neurotransmitters; it also increases non-heme iron absorption.
- Unabsorbed or excess vitamin C is excreted by the kidneys in urine.
Schematic only; positions and scale are not anatomical.
Sources: NIH ODS: VitaminC Fact Sheet for Health Professionals
Daily dose across products (mg/day)
Label data from official national databases and brand websites, as declared; not lab-verified.
Common forms
| Form | Products | Median | P5–P95 | Elemental fraction |
|---|---|---|---|---|
| Ascorbic acid | 5824 | 101 mg | 15 – 1,000 | — |
| Mineral ascorbate (Ca/Na/Mg) | 1341 | 130 mg | 18.8 – 1,000 | — |
| Ascorbyl palmitate | 170 | 13.3 mg | 2 – 500 | — |
Common questions
What is the Daily Value for Vitamin C?
The US FDA Daily Value for adults and children aged 4 and over is 90 mg. It is a labelling reference, not a personal recommendation. [source]
Is there an upper limit for Vitamin C?
The adult Tolerable Upper Intake Level (UL) is 2,000 mg per day. Going above it long term raises the risk of adverse effects. See the linked source. [source]
How much Vitamin C do products usually contain per day?
As of 2026-11-01, 8,730 products list a comparable daily dose (9,257 dose records; one product can have several). The median is 100 mg per day, and 90% of records fall between 10 and 1,000 mg. Figures come from labels and are not lab-tested. [source]
What happens if you take a lot of vitamin C?
It is a water-soluble antioxidant and is needed to make collagen. The bigger the dose, the lower the share absorbed; the excess leaves in urine. Adult UL: 2,000 mg per day. Diarrhoea and nausea are common above it. [source]
What are the side effects of Vitamin C?
Vitamin C has low toxicity and high intakes are not believed to cause serious adverse effects. The most common complaints are diarrhea, nausea, abdominal cramps and other stomach upset, caused by the osmotic effect of unabsorbed vitamin C in the gut. (Source: NIH ODS) [source]
What happens if you take too much Vitamin C?
The adult UL is 2,000 mg a day from food and supplements combined. High doses can raise urinary oxalate and may contribute to kidney stones in people with existing hyperoxaluria or kidney disease, and in hereditary hemochromatosis long-term high doses can worsen iron overload. Above 1 g a day, absorption falls below 50%. (Source: NIH ODS) [source]
Is Vitamin C safe during pregnancy and breastfeeding?
The RDA in pregnancy is 80 mg (ages 14–18) and 85 mg (19+); during breastfeeding it is 115 and 120 mg. The UL in pregnancy and breastfeeding is 1,800 mg (14–18) and 2,000 mg (19+). People who smoke need 35 mg a day more. (Source: NIH ODS) [source]
Does Vitamin C interact with medications or other supplements?
People on chemotherapy or radiation should talk to their oncologist before taking vitamin C or other antioxidant supplements, especially at high doses, because their effect on treatment is disputed. Vitamin C with other antioxidants may blunt the HDL rise from niacin plus simvastatin therapy. (Source: NIH ODS) [source]
Top ranked
| Rank | Brand | Product | Per day | Score |
|---|---|---|---|---|
| 1 | GNC | Vitamin C | 500 mg | 100.0 |
| 1 | New Chapter | Vitamin C 250 mg | 250 mg | 100.0 |
| 1 | Swanson | Vitamin C Powder | 1,000 mg | 100.0 |
| 4 | Nature's Sunshine | Vitamin C | 1,000 mg | 97.8 |
| 5 | Nature's Way | Alive! Vitamin C | 1,000 mg | 94.4 |