Your Guide to Vitamin C: Everything You Need to Know Everyday Health MenuNewslettersSearch Diet & Nutrition Your Guide to Vitamin C What You Need to Know About This Beneficial Nutrient By Amy Gorin, MS, RDNMedically Reviewed by Lynn Grieger, RDN, CDCESReviewed: April 18, 2022Medically ReviewedFruits like kiwis, grapefruits, and oranges — and especially their juices — deliver a lot of vitamin C. Just steer clear of drinks with added sugars.Stefan Cristian Cioata/Getty ImagesAlthough vitamin C is now one of the most common and best-known nutrients, found in everything from cough drops to skin serums, its importance to human health wasn’t always apparent. Vitamin theory, or the idea that the human body needs more than just the macronutrients protein, carbohydrates, and fat to survive, was first introduced around the beginning of the 20th century, and C was only the second vitamin, after thiamine, to be isolated and chemically defined, according to a research paper on the subject. Today, much is known about the various ways vitamin C is used by our bodies, its potential benefits, and the best sources of this all-important nutrient. This guide will explain everything you need to know about this vital vitamin. Common Questions & AnswersWhat is vitamin C good for?Vitamin C, or ascorbic acid, is required by the body to produce collagen, an essential protein found in skin, nails, and hair. Vitamin C also plays a key role in wound healing, iron absorption, and immune function.What are the symptoms of low vitamin C?If you routinely fail to get at least 10 milligrams of vitamin C a day, you can develop scurvy, which is characterized by fatigue, inflamed gums, joint pain, and depression, and can be fatal.What is the best way to get vitamin C?Nutrition experts recommend eating a diet that is plentiful in vitamin C–rich foods, especially fruits, vegetables, and their juices. Excellent sources of vitamin C include red and green bell peppers, oranges and orange juice, kiwi fruit, strawberries, and broccoli.Is it safe to take vitamin C every day?It’s recommended that adults get between 65 and 90 milligrams of vitamin C daily, preferably from foods rich in it. You can also take a supplement or multivitamin that contains vitamin C. Extremely high doses of 2,000 milligrams or more total (from food and supplements), while difficult to achieve, can result in side effects such as diarrhea.Can vitamin C help skin?Vitamin C helps with the production of collagen, a major protein in skin, and its antioxidant properties help shield skin from ultraviolet light. The benefits of oral vitamin C versus topical vitamin C serums are still being investigated. What Is Vitamin C and Why Do I Need It Also known as L-ascorbic acid, or sometimes just ascorbic acid, vitamin C is a water-soluble vitamin that humans, unlike most other animals, cannot synthesize. That means we have to obtain vitamin C through our diets.An important antioxidant, vitamin C helps protect cells from damage caused by illness, aging, and environmental factors like ultraviolet (UV) light and pollution. It’s also required for the body to make collagen, a protein that, among other functions, helps wounds heal. “Vitamin C helps the body repair and regenerate tissues,” says Kate McGowan, RDN, a dietitian in Hingham, Massachusetts.But of all its functions, vitamin C is probably best known for its role in immunity. A study found that being deficient in vitamin C can impair immune function and leave you more susceptible to infections. And supplementing with the vitamin has been shown to help prevent and treat respiratory and other illnesses, possibly because the vitamin supports the immune cells that identify and dispose of foreign particles in the body. While there is no evidence that taking vitamin C will prevent the common cold in the general population, it may help shorter the duration of colds, but only if you have been taking it consistently before getting sick. Immune Building Pantry Dishes Savory Tomato Basil Soup Most Recent in Diet and Nutrition Later Meals Increase Hunger Decrease Calories Burned 6 Bugs You Can Eat and Their Health Benefits 5 Cheap and Healthy Recipes to Make With Oats What Happens to Your Cholesterol When You Go on a Keto Diet What Are the Potential Health Benefits of Vitamin C In addition to its role in immunity, vitamin C may play a part in preventing or lowering the risk of several chronic illnesses. Ongoing research shows that people whose diets are high in vitamin C–rich foods, such as fruits and vegetables, are less likely to develop lung, breast, and colon cancers, and they have lower rates of heart disease. But more research is needed to determine if and to what degree vitamin C alone is responsible for these effects.There is some evidence that taking vitamin C may also help lower blood pressure in patients with hypertension. A meta-analysis of eight randomized controlled trials involving more than 600 participants found that supplementing with vitamin C — the average dose was around 500 milligrams (mg) — led to a significant reduction in blood pressure in participants with high blood pressure, compared with control groups. The effect seemed most pronounced in men age 60 and older. The study authors noted that further research about the long-term effects of vitamin C supplementation is still needed. How Much Vitamin C Do I Need Generally speaking, most healthy adults should get between 65 and 90 mg of vitamin C daily. Some research suggests that certain populations, including pregnant and lactating women, athletes, and smokers, may benefit from a higher intake of vitamin C. Smokers, in particular, have a greater risk of vitamin C deficiency — more than three times greater, according to research. This is likely because smoking causes greater vitamin C turnover in the body. Cigarette smoking increases free radicals in the body, which damages cells; antioxidants such as vitamin C counteract this damage but are depleted more quickly in people who smoke.Likewise, vitamin C supplementation may be helpful to athletes. Specifically, in athletes who experience short periods of extreme physical stress — such as playing in sports competitions — vitamin C may decrease the incidence of the common cold. Ideally, the recommended amount of this micronutrient would come from a diet that is plentiful in vitamin c–rich foods, although the vitamin is also available in supplement form. Adults should be careful not to exceed 2,000 mg per day, however, as this can lead to side effects including diarrhea. What Are the Signs You re Not Getting Enough Vitamin C Vitamin C was discovered, in part, because sailors in the 1700s and 1800s were falling ill and even dying from a lack of the nutrient. The disease, called scurvy, caused weakness, fatigue, and bleeding gums. The cure was ultimately found in citrus fruits, which added vitamin C to a diet that was usually lacking in fresh produce during the sailors’ months at sea. You don’t need much of this essential vitamin to ward off scurvy: Anything more than 10 mg a day will do, which may be why, these days, vitamin C deficiency is rare, affecting only 6 percent of the American population. There is evidence, however, that many Americans don’t meet their recommended daily allowance of the vitamin. Research has shown that between 2003 and 2006, 118 million U.S. adults didn’t get enough vitamin C from their diet alone. And another study found that vitamin C consumption declined by 23 percent between 1999 and 2018, likely as a result of people switching from fruit juice to whole fruit. What Foods Are High in Vitamin C Many fruits and vegetables are good or excellent sources of vitamin C. “Most people associate oranges with vitamin C,” says McGowan. “That is great, but I like to switch it up!” Other excellent sources of vitamin C include: Tomato juice, 170 mg per cupOrange juice, 124 mg per cupRed and green bell peppers, 118 mg per sliced cupStrawberries, 88.2 mg per cupOranges, 82.7 mg per medium naval orangeGrapefruit juice, 76.5 mg per unsweetened cupKiwi fruit, 64 mg per fruitBroccoli, 69.4 mg per cupCantaloupe, 58.7 mg per cup, cubedIt’s important to note that vitamin C is heat sensitive, so you’ll get the most from foods when they’re eaten raw or unheated. Editor s Picks on Immunity 6 Citrus Recipes That Will Help Support Your Immune System 5 Types of Tea That May Support Your Immune System 7 Foods That Fight Back Immune System Boosters Should I Take a Vitamin C Supplement and Can I Overdose “If you are eating a balanced diet, most likely you do not need to take a vitamin C supplement,” says McGowan. Vitamin C is water-soluble — meaning the body utilizes it but doesn’t store it.“For most healthy individuals, the body can only hold and use about 200 to 250 mg of vitamin C a day, and any excess is lost through urine,” explains McGowan.Despite this, you can overconsume vitamin C. This is most likely to occur with supplement use, so make sure your total daily intake (including food and supplements) falls below the tolerable upper limit, or the maximum daily intake of 2,000 mg recommended for healthy adults. Keep in mind that if you take a multivitamin, you’re also getting vitamin C there, so don’t forget to add that amount to your total supplemental intake. What Are Potential Side Effects of Vitamin C High doses of vitamin C may contribute to the formation of kidney stones, as well as severe diarrhea, nausea, and gastritis. Research that looked at more than 23,000 men with no history of kidney stones found that those who took around 1,000 mg of ascorbic acid supplements had double the risk of developing kidney stones, compared with men who only took a multivitamin or men who didn’t take any dietary supplements. The risk of kidney stones was highest among men who took vitamin C at least once a day. The study authors note that the risk may not apply to women, who generally have a lower risk of kidney stones. Another study looked at data on both men and women and concluded that vitamin C intake, regardless of whether it came from diet or supplements, was significantly associated with a higher risk of incident kidney stones in men, but not among women. Those results were found in people with an intake greater than 700 mg per day. Additionally, vitamin C supplements have the potential to interact with several types of medications, including statins and certain chemotherapy drugs. People who are receiving chemotherapy, radiation therapy, or taking prescription medications should speak with their healthcare provider before taking vitamin C supplements. Most Popular in Diet and Nutrition Whole30 Beginner s Guide What to Eat and Avoid Advantages and More What Is the Golo Diet A Complete Scientific Guide 10 Healthy Foods That Are Great Sources of Iron 7 Potential Health Benefits of Mushrooms What s Vitamin C Serum and Should I Use It on My Skin While vitamin C is the antioxidant most present in human skin, only a small amount of the vitamin you consume makes its way there — even when you supplement orally. That’s why you see bottles of vitamin C serum in the drugstore.Vitamin C serums can be topically applied to the skin and may provide benefits such as protection against damage caused by UV exposure, including collagen damage and wrinkling. And while it’s no replacement for sunscreen, a vitamin C serum routinely applied before sun exposure may help prevent premature aging of the skin. It may also help protect against pigmentation issues by interfering with melanin synthesis. You’ll see many varieties of vitamin C serums — including ones with additional ingredients, such as vitamin E or hyaluronic acid. Summary Vitamin C is an essential micronutrient that we need to get through our diet, preferably through a variety of whole foods like fruits and vegetables. It plays a role in a number of important bodily functions, including immunity and skin health, and it may help prevent several chronic diseases, so getting your recommended daily allowance can help ensure that your body is working optimally. Additional reporting by Jill Waldbieser. Editorial Sources and Fact-Checking Semba RD. The Discovery of the Vitamins. International Journal for Vitamin and Nutrition Research. October 2012.Vitamin C: Fact Sheet for Health Professionals. National Institutes of Health Office of Dietary Supplements. March 26, 2021.Pullar JM, Carr AC, Vissers MCM. The Roles of Vitamin C in Skin Health. Nutrients. August 2017.Guan Y, Dai P, Wang H. Effects of Vitamin C Supplementation on Essential Hypertension. Medicine: February 2020.Carpenter KJ. The Discovery of Vitamin C. Annals of Nutrition and Metabolism. November 2012.Carr AC, Maggini S. Vitamin C and Immune Function. Nutrients. 2017.Shaik-Dasthagirisaheb YB, Varvara G, Murmura G, et al. Role of Vitamins D, E and C in Immunity and Inflammation. Journal of Biological Regulators and Homeostatic Agents. April–June 2013.Narayanan S, Kumar SS, Manguvo A, Friedman E. Current Estimates of Serum Vitamin C and Vitamin C Deficiency in the United States. Current Developments in Nutrition. June 2021.Brauchla M, Dekker MJ, Rehm CD. Trends in Vitamin C Consumption in the United States: 1999–2018. Nutrients. January 2021.Li N, Zhao G, Wu W, et al. The Efficacy and Safety of Vitamin C for Iron Supplementation in Adult Patients with Iron Deficiency Anemia: A Randomized Clinical Trial. JAMA Network Open. November 2, 2020.Vitamin C. MedlinePlus. April 1, 2022.Bucher A, White N. Vitamin C in the Prevention and Treatment of the Common Cold. American Journal of Lifestyle Medicine. May–June 2016.Cerullo G, Negro M, Parimbelli M, et al. The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19. Frontiers in Immunology. October 2020.Carr AC, Rowe S. Factors Affecting Vitamin C Status and Prevalence of Deficiency: A Global Health Perspective. Nutrients. July 2020.Foundation Foods. U.S. Department of Agriculture. April 2021.Thomas LDK, Elinder C, Tiselius H, et al. Ascorbic Acid Supplements and Kidney Stone Incidence Among Men: A Prospective Study. JAMA Internal Medicine. March 11, 2013.Ferraro PM, Curhan GC, Gambaro G, Taylor EN. Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones. American Journal of Kidney Diseases. March 2016.Show LessNEWSLETTERS Sign up for our Diet and Nutrition Newsletter SubscribeBy subscribing you agree to the Terms of Use and Privacy Policy. 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