Unlike animals, humans cannot synthesize vitamin C on our own. Therefore, you must get enough of it from foods or supplements to maintain good health.

Vitamin C is a water-soluble nutrient with many vital functions in your body.

It helps strengthen your immune system, aids collagen production and wound healing, and acts as an antioxidant to protect your cells from free radical damage (1, 2, 3, 4, 5, 6, 7).

Vitamin C is also known as L-ascorbic acid, or simply ascorbic acid.

Let’s go over the recommended dosage of vitamin C for optimal health.

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What’s the recommended intake?

The Institute of Medicine (IOM) has developed a set of reference values for specific nutrient intake levels, including for vitamin C.

One set of guidelines is known as the Recommended Dietary Allowance (RDA) and considers average daily nutrient intake from both foods and supplements.

RDA recommendations for specific gender and age groups should meet the nutrient needs of 97–98% of healthy individuals (10).

Here are the RDAs for vitamin C (11):

Life stageRDAKids (1–3 years)15 mgKids (4–8 years)25 mgAdolescents (9–13 years)45 mgTeens (14–18 years)65–75 mgAdult women (aged 19 and older)75 mgAdult men (aged 19 and older)90 mgPregnant women (aged 19 and older)85 mgBreastfeeding women (aged 19 and older)120 mg

In addition to the RDA recommendations for vitamin C, the Food and Drug Administration (FDA) has issued a recommended Daily Value (DV).

The DV was developed for food and supplement labels. It helps you determine the percentage of nutrients in a single serving of food, compared with the daily requirements. On food labels, this is displayed as %DV (12).

Currently, the recommended DV for vitamin C for adults and children aged 4 and above is 60 mg regardless of gender. However, in January 2020, this will increase to 90 mg (8).

Summary

The RDA for Vitamin C ranges from 15–75 mg for children, 75 mg for adult women, 90 mg for adult men, and 85–120 mg for women who are pregnant or breastfeeding.

May benefit some conditions

Vitamin C is essential for overall health and wellness, and the nutrient may particularly benefit certain conditions.

The vitamin is especially helpful for immune health, as it supports your immune system’s cellular function (13).

In fact, vitamin C supplements may help prevent infection, while a deficiency of the vitamin appears to make you more susceptible to infection (13, 14, 15.)

For example, some research suggests that although regular vitamin C intake likely won’t prevent you from catching a cold, it may reduce the duration or severity of cold symptoms (16).

A review of 31 studies found that consuming 1–2 grams of vitamin C daily reduced cold duration by 18% in children and 8% in adults (16).

In addition, it’s known that vitamin C increases iron absorption. Thus, individuals with iron deficiency might benefit from increasing their vitamin C intake (17, 18)

Summary

Regularly getting 1–2 grams of vitamin C per day may reduce the duration of common cold symptoms and boost your immune system. It might also help prevent iron deficiency anemia.

Best food sources

Typically, the best sources of vitamin C are fruits and vegetables.

It’s important to note that vitamin C in food is easily destroyed by heat, but since many good sources of the nutrient are fruits and vegetables, simply eating some of those foods raw is an easy way to reach the recommended intake.

For example, a 1/2-cup (75-gram) serving of raw red pepper provides 158% of the RDA set by the IOM (8).

The table below displays the vitamin C content and contribution to the recommended Daily Value (DV) for some of the best food sources of the nutrient (8).

This table is based on the current 60-mg recommendation, but since any food providing 20% or more of the DV for vitamin C is considered a high source, many of these foods will still be great sources after the DV recommendation is changed to 90 mg in January 2020 (8).

Great food sources of vitamin C include:

FoodAmount per serving%DVRed pepper,
1/2 cup (75 grams)95 mg158%Orange juice,
3/4 cup (177 ml)93 mg155%Kiwifruit, 1/2 cup (90 grams)64 mg107%Green pepper,
1/2 cup (75 grams)60 mg100%Broccoli, cooked,
1/2 cup (78 grams)51 mg85%Strawberries, fresh,
1/2 cup (72 grams)49 mg82%Brussels sprouts, cooked,
1/2 cup (81 grams)48 mg80%summary

The best food sources of vitamin C are fruits and vegetables. The nutrient is easily destroyed by heat, so consuming these foods raw might maximize your nutrient intake.

Best vitamin C supplements

When looking for a vitamin C supplement, you might see the nutrient in a couple different forms (8):

• ascorbic acid
• mineral ascorbates, such as sodium ascorbate and calcium ascorbate
• ascorbic acid with bioflavonoids

Choosing a supplement with ascorbic acid is usually a good choice, as it has a high level of bioavailability, meaning your body absorbs it easily (8, 19, 20, 21).

Additionally, given that most multivitamins contain ascorbic acid, choosing a multivitamin will not only boost your vitamin C intake but also your intake of other nutrients.

To ensure you’re receiving adequate amounts of vitamin C from the supplement you choose, look for a supplement that provides between 45–120 mg of this vitamin depending on your age and sex.

summary

Vitamin C supplements come in a variety of forms. Choose a supplement with ascorbic acid to make it easier for your body to absorb the nutrient.

Can you take too much?

Although vitamin C has an overall low toxicity risk in healthy individuals, consuming too much of it can cause some adverse gastrointestinal side effects, including cramps, nausea, and diarrhea (11, 22).

Additionally, since a high vitamin C intake increases the body’s absorption of non-heme iron, consuming too much vitamin C could cause problems for people with hemochromatosis, a condition in which the body retains too much iron (23, 24, 25, 26).

Because of the potential side effects of excessive vitamin C, the IOM has established the following Tolerable Upper Intake Levels (UL) for the vitamin (11):

Life stageULKids (1–3 years)400 mgKids (4–8 years)650 mgAdolescents (9–13 years)1,200 mgTeens (14–18 years)1,800 mgAdults (aged 19 and older)2,000 mgsummary

To avoid gastrointestinal side effects, keep your vitamin C intake within the ULs established by the IOM. Individuals with hemochromatosis should be particularly cautious when taking vitamin C supplements.

The bottom line

Vitamin C is a water-soluble vitamin and essential antioxidant that plays many roles in your body. It supports wound healing, collagen formation, and immunity.

The RDA for vitamin C is 45–120 mg depending on your age and sex.

Vitamin C supplements should meet the RDA and stay well below the established UL — 400 for young children, 1,200 mg for kids aged 9–13, 1,800 mg for teens, and 2,000 mg for adults.

Consuming a variety of vitamin-C-rich fruits and vegetables can also go a long way in supporting optimal health and wellness.