Vitamin C 101

Learn more about vitamin C (aka ascorbic acid), what it does for the body and how to make sure you're getting enough of this powerful antioxidant.

Medically reviewed by Revée Barbour, MD NS
March 28, 2023

Both a micronutrient and antioxidant, vitamin C does a lot for your body. On the most basic level, it is necessary for your body to create collagen, a key component of connective tissue, so it helps the body form and repair connective tissues throughout the body, including bones, skin and blood vessels. And that’s just the beginning.

Immune function

Perhaps its most well-known benefit is vitamin C’s role in immune function. It’s essential for a number of cellular and enzymatic functions throughout the body, and supports both our innate and adaptive immune response. As an antioxidant, vitamin C also supports our immune function by protecting against pathogens and environmental stressors.

Collagen production

Vitamin C plays a significant role in the production of collagen, a protein the body uses to make skin, cartilage, tendons, ligaments and other connective tissues. “Healthy collagen levels not only help to slow down the signs of aging, but also, may help reduce joint pain associated with weakened joints due to loss of collagen,” says Revée “Dr. Ray” Barbour, ND MS.

Brain and nervous system function

Our neurological function depends on vitamin C, too. In a nutshell, vitamin C supports a healthy central nervous system by helping to stimulate the production of various enzymes involved in cognition. The brain naturally produces these enzymes, but without enough vitamin C, that production slows.

Antioxidant activity

Antioxidants such as vitamin C, vitamin E and beta carotene block some of the damage (or oxidation) caused by free radicals, substances that can build up in the body and damage cells. Exactly how free radicals accumulate is up for debate, but what we do know is that over time, this buildup may contribute to the aging process as well as the development of certain health conditions.

How does vitamin C work?

In supporting various cellular functions in the body, vitamin C fills different roles:

• Tissue builder: Vitamin C helps to form and maintain tissues including skin, blood vessels, and muscle.
• Antioxidant: Your body needs vitamin C’s antioxidant action to help reduce levels of free radicals,prevent environmental damage and build your overall resistance to illness.
• Immune supporter: While we know vitamin C doesn’t actually cure colds, it is an important part of a healthy immune response. Because vitamin C is a water-soluble compound, our bodies don’t store it, so we need to replenish our supply every day, ideally through diet.

Why do we need vitamin C?

In short, vitamin C is necessary for:

• Generating the most prevalent protein in the body—collagen
• Absorbing iron
• Regulating multiple immune functions

How long does it take for your body to absorb vitamin C?

As long as you get close to your recommended daily amount of vitamin C, your body absorbs the majority of it—about 80%—within 24 hours.

Is vitamin C good for kids?

Yes—vitamin C is an essential vitamin that both children and adults need daily.

Because our bodies can’t produce vitamin C on their own, Dr. Ray emphasizes, “it’s important to ‘Eat the Rainbow’ in a variety of brightly colored fruits and vegetables every day to support a healthy diet for both you and your child.” If you have a picky eater at home or have any concerns about your child’s nutrition, you can ask your pediatrician or naturopathic doctor about whether adding supplements to their diet is a good option.

Is vitamin C good for you?

Not only is vitamin C good for you—it’s a vital nutrient that protects healthy cells in your body and is a key part of numerous cellular functions. You can read more about the benefits of vitamin C here and in the “What does vitamin C do?” section above.

As we already mentioned, our bodies don’t produce vitamin C on their own, so we have to make sure we get enough through foods or supplements. According to the National Institutes of Health (NIH), the RDA of vitamin C is as follows for adults age 18 and up:

• Men: 90 mg
• Women: 75 mg
• Pregnant women: 85 mg
• Breastfeeding women: 120 mg

The RDAs of vitamin C for teens and children are:
• Toddlers 1-3 years old, 15 mg per day
• Children 4-8 years old, 25 mg per day
• Children 9-13 years old, 45 mg per day
• Male teens 14-18 years old, 75 mg per day
• Female teens 14-18 years old, 65 mg per day

For infants under age 1, NIH recommends Adequate Intakes (AIs):
• 0-6 months old: 40 mg per day
• 7-12 months old: 50 mg per day

The best way to make sure you get enough of your daily dose of vitamin C (and other essential vitamins and minerals) is to eat a variety of whole foods, including plenty of fruits and veggies. There are many foods that are high in vitamin C, and, spoiler—they’re not all citrus fruits! Take your pick:

• Bell peppers (red, green)
• Blueberries
• Broccoli
• Brussels sprouts
• Cantaloupe
• Citrus fruits (oranges, grapefruit, etc.)
• Cranberries
• Kiwi
• Lemons
• Papaya
• Pineapple
• Raspberries
• Spinach, kale and other leafy greens
• Strawberries
• Sweet and white potatoes
• Tomatoes and tomato juice
• Watermelon
• Winter squash

Vitamin C side effects

Because our bodies can’t store vitamin C, side effects from too much of it are pretty rare. The average healthy person’s body can only hold and use about 200 to 250 mg of vitamin C a day (any extra is lost through urine).
Still, overdoing it isn’t a good idea. High doses of vitamin C (more than 2,000 mg/day) could increase your risk of developing kidney stones or lead to gastrointestinal symptoms like upset stomach or diarrhea.
As with any supplement, vitamin C has potential interactions with some other medications including:

• Aspirin and NSAIDs
• Acetaminophen
• Barbiturates
• Certain chemotherapy drugs
• Oral contraceptives
• Protease inhibitors
• Tetracycline
• Warfarin, a type of blood thinner

With all of this in mind, always consult a doctor or health care provider before taking any new supplement.