Key Takeaways
- Adults should get 75 to 90 milligrams (mg) of vitamin C every day.
- Smokers should add 35 mg more vitamin C to their daily intake.
- Vitamin C helps your body absorb iron and boosts immune health.
You must get enough vitamin C daily from food or supplements, as the body does not store it and it eliminates any excess in the urine. The recommended amount of vitamin C per day varies by age and sex, as well as pregnancy, lactation, and smoking status.
Recommended Daily Allowance (RDA) by Life Stage
You need to get enough vitamin C to support your immune health and other body functions. Most people do not need vitamin C supplementation because they get enough in food and drinks, and vitamin C deficiency is rare in the United States.
The National Institutes of Health (NIH) recommends the following dietary intakes of vitamin C daily:
- Babies and infants: 40 mg from birth to 6 months, 50 mg 7 to 12 months
- Children ages 1 to 3: 15 mg
- Children ages 4 to 8: 25 mg
- Children ages 9 to 13: 45 mg
- Teens ages 14 to 18: 65 mg for females, 75 mg for males
- Adults: 75 mg for females, 65 mg for males
- In Pregnancy: 80 mg age 14 to 18, 85 mg age 19 and over
- While Lactating: 115 mg age 15 to 18, 120 mg age 19 and over
- Smokers: Need additional 35 mg daily
If you are pregnant, it is not a good idea to take vitamin C supplements without first talking to a healthcare provider.
Foods vs. Supplements
Many foods contain vitamin C, especially fruits and vegetables. You can get the recommended amounts of vitamin C from food if you are eating a balanced diet. For most people, getting their vitamin C from food is better than taking supplements.
Who Might Especially Benefit From Vitamin C?
Research shows that some people may benefit from a higher vitamin C intake. This includes:
- Smokers and people exposed to secondhand smoke: Smokers have an up to three times higher risk for vitamin C deficiency due to a more significant turnover of vitamin C in the body. Cigarette smoking increases the production of damaging free radicals in the body, which deplete antioxidants (such as vitamin C) that counteract them. Exposure to secondhand smoke can also decrease vitamin C levels.
- Infants fed evaporated or boiled milk: Infants in developed countries are fed human milk and/or infant formula, which are vital to meeting vitamin C requirements. However, infants who are given evaporated or boiled milk cannot meet their daily vitamin C recommendations.
- People with limited food options: People lacking access to fruits and vegetables may not get enough vitamin C in their diets. This can include older adults, those who can’t prepare their own food, people with alcohol or other substance use disorders, people with mental illness, and children.
- People with malabsorption and certain chronic diseases: Some medical conditions can reduce the body’s ability to absorb vitamin C. Conditions that may lead to malabsorption include celiac disease, lactose intolerance, cystic fibrosis, and bowel resection.
Additional health factors can affect a person’s vitamin C status. These include:
- Body weight
- Disease states, including severe infections and conditions like cardiovascular disease and cancer
- Genetics
- Pregnancy and lactation
How Much Vitamin C Do You Need for Specific Goals?
Boosting Immunity
Ways in which vitamin C can boost the immune system include:
- It encourages the production of white blood cells that protect the body from infection.
- It helps white blood cells function more effectively while protecting them from free radicals. These harmful molecules are responsible for oxidative stress and chronic disease.
- It may prevent and treat respiratory and systemic infections, although it is not proven to prevent or treat colds. For a preventive effect, you would need at least 100–200 mg per day. However, treating an infection would require significantly higher doses of vitamin C to reduce the inflammatory response and metabolic demand.
- It plays a vital part in the skin’s defense system, acting as an antioxidant, supporting collagen production, protecting skin from sun damage, promoting wound healing, and boosting skin hydration.
Low levels of vitamin C are linked to poor health outcomes. Research shows that low vitamin C can put people at risk for inflammatory conditions.
Reducing Cancer Risk
Some research suggests that vitamin C intake in foods may reduce the risk of some cancer types. A 2021 Antioxidants review finds that consuming vitamin C from foods could potentially decrease the risk of pancreatic, breast, and pulmonary cancers. Still, more research is needed to confirm such findings.
The same report also suggests that vitamin C can be administered in high intravenous doses to treat certain cancers. Research on safety and efficacy in this area is ongoing.
Lowering Risk for Metabolic Syndrome
Vitamin C may help lower your risk for conditions associated with metabolic syndrome. Metabolic syndrome is a cluster of conditions that increase the risk of heart attack, stroke, and diabetes. These conditions are high blood pressure, high blood sugar, abdominal obesity, high triglyceride levels, and low high-density lipoprotein (HDL) cholesterol (considered “good” cholesterol).
Research on vitamin C supplementation has shown reduced risk and improved conditions. The dosing for such studies falls between 100 mg and 150 mg.
Improving Cardiovascular Health
According to a 2020 review, Vitamin C has positive effects on cardiovascular health and blood flow. While the effects of vitamin C on heart health are promising, the authors note that more research is needed to confirm whether vitamin C alone can prevent cardiovascular disease.
Most clinical studies recommend 500 to 1,000 mg of vitamin C daily for heart health. The NIH’s daily recommendations are much lower, at 75 mg to 90 mg.
Managing Blood Pressure
Studies have found that vitamin C may help to lower blood pressure in both people with hypertension (high blood pressure) and people without the condition.
One 2024 study aimed to evaluate the effect of a vitamin C supplement (130 mg) with a beverage containing 278.7 mg of flavonoids.
The results showed that vitamin C and flavonoids helped to prevent elevated blood pressure caused by heat exposure. The researchers attributed this to how vitamin C inhibits oxidative stress. While these results are promising, the long-term effects of vitamin C on blood pressure are not known.
Reducing Uric Acid
Gout is a type of arthritis caused by high uric acid levels. It involves inflammation of the joints, often in the big toes. Gout attacks can cause severe swelling and pain.
A 2021 study found a strong link between vitamin C supplementation and decreased uric acid levels. In this study, a 500 mg daily vitamin C intake reduced uric acid levels.
While the researchers found the findings promising, they did not feel there was enough evidence to recommend vitamin C supplementation as a method of gout prevention or treatment.
Preventing Iron Deficiency
If you have an iron deficiency, your body does not have enough iron to produce the hemoglobin in red blood cells that carries oxygen to your organs and tissues. Vitamin C can improve iron absorption.
One 2020 clinical trial examined the effect of oral iron supplements and iron supplements in combination with vitamin C on treating iron deficiency anemia. It found that combining iron and vitamin C improved hemoglobin levels much better than treating with iron alone.
The dosing in this study was 100 mg iron and 200 mg vitamin C.
Promoting Eye Health
A specific combination of vitamin C with other vitamins and nutrients may the risk of progression of dry age-related macular degeneration (AMD), but it does not prevent or cure the condition. The AREDS2 formula may be recommended.
Vitamin C has not been proven to delay the development of cataracts, a clouding of the eye’s normally clear lens caused by aging and diabetes.
Can You Get Too Much Vitamin C?
If you take more than 2,000 mg of vitamin C at once, you will most likely experience digestive symptoms. GI side effects and headaches are commonly seen in people who take high doses of vitamin C supplements.
Vitamin C toxicity is rare. The most common side effect of high vitamin C is gastrointestinal (GI) distress.
Top Foods Packed With Vitamin C
All fruits and vegetables contain vitamin C. Raw fruits and vegetables are the best sources of vitamin C. Cooking vitamin-rich foods or storing them for long periods can reduce their amount of vitamin C.
Fruits with the highest amounts of vitamin C include:
- Berries, such as strawberries, raspberries, blueberries, and cranberries
- Cantaloupe
- Citrus fruits and juices
- Kiwifruit
- Tropical fruits, including mango and pineapple
- Watermelon
Vegetables from the highest amounts of vitamin C include:
- Cruciferous vegetables, such as broccoli, brussels sprouts, and cauliflower
- Green and red peppers
- Leafy green vegetables, including spinach, cabbage, and kale
- Sweet and white potatoes
- Tomatoes and tomato juice
- Vegetable juices
Various cereals, foods, and beverages are fortified with vitamin C. This means that vitamin C has been added to them. Check product labels to see which foods and beverages are vitamin C fortified.
| High Vitamin C Foods | ||
|---|---|---|
| Food | Vitamin C per Cup/Daily Value (DV) | Vitamin C per 100 mg/Daily Value |
| Guava | 377 mg /419% DV | 228 mg/254% DV |
| Kiwifruit | 167 mg/185% DV | 93 mg/103% DV |
| Strawberries | 98 mg/108% DV | 59 mg/65% DV |
| Oranges | 96 mg/106% DV | 53 mg/59% DV |
| Broccoli | 81 mg/90% DV | 89 mg/99% DV |
| Tomatoes | 55 mg/61% DV | 23 mg/25% DV |
| Kale | 23 mg/26% DV | 18 mg/20% DV |
What to Look for in a Vitamin C Supplement
When purchasing vitamin C supplements, consider:
- Quality: Purchase your supplements from reputable companies that source ingredients well and follow the Food and Drug Administration (FDA) guidelines for Good Manufacturing Processes.
- Form: The main form of vitamin C is ascorbic acid. Research has not found significant differences among various chemical formulations.
- Packaging: Choose supplements sold in dark or tinted glass bottles and airless delivery to prevent oxidation and degradation of the vitamin.
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