What Happen​s to Your Body When You Take Vitamin C Every Day

It may take a sniffly nose, constant sneezing or a pesky cough to bring vitamin C top-of-mind. Getting sick reminds you of your immune function, which may leave you wondering whether you should take vitamin C daily. Vitamin C is a well-known vitamin in citrus fruits that many people turn to when under the weather. That's because it can enhance immune health and may shorten how long a cold lasts, per MedlinePlus. 

Vitamin C is a crucial nutrient and antioxidant that aids in producing compounds that support different body functions. So, can you benefit from taking a regular vitamin C supplement? Does it really “boost” your immune system? How much is too much?  Read on to learn more about what happens when you take vitamin C every day.

What Is Vitamin C?

Vitamin C, or L-ascorbic acid, is a water-soluble vitamin naturally present in food. Though most mammals can make vitamin C in their bodies without problem, humans must get it through the diet via foods or supplements, per a 2019 review in Pharmacological Research. According to the National Institutes of Health, the Recommended Dietary Allowance of this nutrient for those 19 years or older is 90 milligrams for males and 75 mg for females.

Vitamin C is necessary to form collagen, a vital part of connective tissue, which helps mend wounds. Additionally, vitamin C promotes absorption of iron —especially non-heme, the type of iron found in plants, per a 2021 review in Nutrients. The immune-supportive vitamin moonlights as an antioxidant and regenerates other antioxidants in the body. It assists in making L-carnitine and supports energy and protein metabolism. Parts of the body with the highest levels of vitamin C include the eyes, pituitary gland, adrenal glands and brain. Speaking of the brain, a 2022 study in the European Journal of Nutrition noted that vitamin C protects neurons (brain cells) against oxidative stress and may be helpful to mental health.

Food Sources

Vitamin C camps out in plenty of nourishing sources eaten worldwide, and many foods have more vitamin C than—you guessed it—an orange!

Some vitamin C sources are:

• Citrus fruits such as lemons, limes, grapefruit
• Tropical fruits such as pineapple, lychees, guava, papaya 
• Kiwi
• Strawberries
• Tomatoes
• Cruciferous veggies, such as broccoli, Brussels sprouts, kale, cabbage
• Bell peppers
• Potatoes

Vitamin C Deficiency

Most people have sufficient vitamin C intake because many consume foods naturally rich in vitamin C or fortified with it. Yet, others may need more. According to the National Cancer Institute, 7% of people in the U.S. have scurvy, a condition where vitamin C levels fall below normal. Scurvy happens from eating too few vitamin C sources or impaired absorption in the digestive tract. 

Symptoms of vitamin C deficiency include:

• loss of teeth
• swollen, bleeding gums
• muscle weakness
• poor wound healing
• anemia
• weight loss
• hyperkeratosis (thickening of the skin's outer layer)
• arthralgia (stiff joints)

Vitamin C Supplements

Even if you don’t have vitamin C deficiency, catching a cold can make you lose trust in your immune system, and a store run for vitamin C immune-supporting powder may be the natural thing to do. 

According to the NIH, most supplements containing vitamin C come in the form of ascorbic acid. However, other forms include sodium ascorbate, calcium ascorbate, other mineral ascorbates or combination products. Research has shown that your body's ability to absorb (or the bioavailability of) synthetic ascorbic acid appears to be the same as from natural sources. That means that simple ascorbic acid is the preferred form of vitamin C supplementation.

Benefits

May Support Your Immune Health

While it's common to find bare shelves of vitamin C during flu season, how it impacts immunity is unclear. That said, we do know the skin needs normal levels of vitamin C to maintain a healthy barrier to keep harmful pathogens from entering the body, per a 2023 review in Mucosal Immunology. Vitamin C is also present in immune cells, so having sufficient levels is vital. Low levels of vitamin C could make you more susceptible to sickness. As an antioxidant, vitamin C protects cells from oxidative damage and regulates anti-inflammatory pathways, helping reduce inflammation and, therefore, the risk of chronic health conditions.

May Prevent Lead Poisoning

Consuming vitamin C may help alleviate lead exposure. Lead is a heavy metal found in some paint, jewelry, soil and other products that is poisonous in high concentrations. Even the most minor blood levels of lead can impact how well a child performs in school. According to the Centers for Disease Control and Prevention, routinely eating foods rich in iron, calcium and vitamin C may help keep lead away. However, more research is needed to understand the beneficial effects. 

Might Improve Your Iron Levels

According to a small 2022 study published in the International Journal of Environmental Research and Public Health, iron deficiency is the most prevalent micronutrient deficiency. Populations most at risk are infants, young children, pregnant people and females of reproductive age. The CDC recommends improving iron absorption by pairing an iron-rich food with a vitamin C-rich food, such as mandarin oranges with salad greens. Some studies have seen significant differences in iron levels when supplementing with vitamin C and iron compared to iron alone, per a 2022 article in ACS Omega.

Potential Risks

May Increase Your Risk for Toxicity

According to the NIH, overloading yourself with vitamin C is unlikely, but still possible. Digestive upset, including stomach cramps, diarrhea and nausea, commonly occurs when unabsorbed vitamin C is in the intestines. High vitamin C levels can cause increases in oxalates, which make you more prone to kidney stones, especially for people with poor kidney function, per the NIH. 

Vitamin C doses greater than 1 gram may increase the chances of stone formation by 41%, per the 2021 review in Nutrients. The same review reported women taking too much vitamin C during pregnancy could result in rebound scurvy in newborn babies. Excess vitamin C may also affect vitamin B12 and copper levels and cause dental enamel erosion. Because of these health risks, an upper limit for adults ages 19 and up is 2,000 mg daily, per the NIH. However, some people may be taking more under the supervision of a medical provider.

What to Look For in a Vitamin C Supplement

In a 2020 Consumer Lab Vitamin and Supplement Users Survey of 9,782 people, nearly 35% reported buying vitamin C the previous year. Shopping for a supplement can be tricky, with shelves of supplements available. It’s important to consult your health care provider before starting any supplement. 

Forms

You can find vitamin C supplements in various forms, such as powders, gummies, chewable tablets, non-chewable tablets and capsules. When looking for one, consider what form of vitamin C will help you be consistent. If mixing powdered vitamin C with water isn't for you, you might choose chewable. If you dislike swallowing pills, you may enjoy gummies, but if you are sensitive to added sugar, you might opt for a capsule. Choose the form that works best for your lifestyle.

Ingredients

Take a close look at supplement ingredient lists to pinpoint any additives it may have, such as artificial colors, added sugars, preservatives or fillers. According to the Food and Drug Administration, supplement labels list these under "other ingredients." For information on FDA communication about ingredients, you can use the FDA's Dietary Ingredient Supplement Directory.

Reputable Manufacturer and Third-Party Verification

The FDA doesn't regulate supplements. You can still take steps to ensure your supplement is reliable, safe and effective. Third-party labeling can help identify a trustworthy supplement. USP, NSF and ConsumerLabs are examples of third-party labels to seek on the packaging or bottle to help ensure you're getting honest ingredients.

Frequently Asked Questions

Is it safe to take vitamin C supplements every day?

Vitamin C can be safe to take daily; however, it's helpful to know that you can meet your daily needs by eating vitamin C-rich foods. For instance, a half-cup of kiwi offers 134 mg of vitamin C, which provides 148% to 178% of recommended daily needs. Before taking any new supplements, it's best practice to speak with your medical provider and stay below the upper limit for vitamin C.

What is the best form of vitamin C to take?

Nothing beats getting vitamin C from whole foods, which is the ultimate form. Many foods are brimming with vitamin C, like citrus fruits, cruciferous veggies and potatoes. If you're still interested in a vitamin C supplement, the best form to take is synthetic ascorbic acid and the presentation you can easily ingest, which for some could be a mixable powder and, for others, an easy-to-swallow capsule.

Are vitamin C supplements good for you?

Vitamin C supplements can benefit people, especially those with low vitamin C levels. But vitamin C-rich foods, packed with many other essential vitamins and minerals, are better for you.

Who should avoid taking vitamin C?

According to the NIH, hemochromatosis, a condition where people have dangerously high iron levels, can worsen with high intakes of vitamin C—leading to tissue damage.

The Bottom Line

Supplements can be costly, and a routine daily dose of a vitamin C supplement isn't necessary for healthy people. Most people have healthy vitamin C levels. Talk to your health care provider first if you're considering taking a vitamin C supplement. Otherwise, if you're concerned about getting enough vitamin C foods, simply turn to your local market and stock up on vitamin C-rich fruits and vegetables. Whether fresh, frozen or canned, produce like pineapple, potatoes and bell peppers are plentiful in vitamin C, and enjoying more of them can meet your everyday needs.