nutrition

Is It Possible to Take Too Much Vitamin C When You're Getting Over the Sniffles?

Dr. Carla Montrond Correia ND, CNS

Medically Reviewed by

Dr. Carla Montrond Correia ND, CNS

4 min read

a put of tea with a slice of lemon on top

Vitamin C is more than just a delicious glass of orange juice. It’s plentiful in most healthy diets. But if you’re not getting enough, does a supplement help?

Vitamin C is probably one of the most well-known and oft-used supplements available today. People reach for supplements for their quick dose of immune support. But does it help?

What is Vitamin C?

Vitamin C, also known as L-ascorbic acid, is a water-soluble micronutrient that is found in a variety of foods including citrus fruit, strawberries, bell peppers, cruciferous vegetables like broccoli and cauliflower, tomatoes, and white potatoes. It is a strong antioxidant that helps protect the body from harmful free radicals, supports seasonal lung and sinus issues, and helps heal wounds. It is also essential for the production of collagen, a protein found in connective tissue throughout many systems in the body.

Because vitamin C is water-soluble, excess amounts of it that are not being used are excreted through urine rather than stored in the body. This means that your body requires a daily intake ideally through diet but, if warranted, supplementation.

Is it possible to take too much vitamin C?

The recommended maximum daily intake of vitamin C for adults is 2,000 mg per day. Since it is water-soluble, excess vitamin C (over 1,000 mg) will not be absorbed. Instead, it will be easily expelled in urine and unlikely to cause any significant problems. People with excess iron in their system should be cautious with higher doses, and those with kidney issues should, according to this source, keep their dosage below 500 mg. It is important to discuss any supplementation with your physician.

Symptoms of taking too much vitamin C

Although too much vitamin C in healthy adults is unlikely to be harmful, and you will likely expel excess in your urine, it could result in digestive symptoms such as diarrhea, vomiting, stomach cramps, and indigestion especially when vitamin c is not buffered and simply in ascorbic acid form.

Can vitamin C help boost immunity?

A number of studies have found that adequate intake of vitamin C will support the human immune system, while reducing reactive oxidative species thanks to its antioxidant properties. One study of ultramarathoners demonstrated that 600 mg of vitamin C daily reduced the incidence of post-race lung and sinus issues among these competitive athletes and may do the same in the more sedentary population. While other studies have found a more mixed bag of results, nobody debates the need for a healthy diet rich in vitamin C.

How does vitamin C play a role with your immune system?

The immune system is a complex network of tissues, organs, cells, proteins, and chemicals that is designed to protect the body from foreign invaders. There is a close relationship between nutritional health and optimal immune function, and adequate amounts of vitamin C are necessary for a healthy immune system. In conjunction with vitamin D and zinc, vitamin C supports both the innate and adaptive immune systems, the epithelial barrier function, phagocyte cells, natural killer (NK) cell functions, and lymphocyte proliferation and differentiation. The trio of C, D, and zinc are actively used by cells of the immune system while engaged in promoting a healthy immune response to free radicals. Many factors can cause free radicals, such as stress, diet, pollution and other environmental factors.

How to best supplement vitamin C

If you don’t already have a preferred brand of supplements, ask your physician, close family members, and friends for recommendations. As always, do your homework. There are a multitude of vitamin C supplements available in liquid, powder, chewable tablet, and pill form. You should always use a high quality, high potency supplement, checking for dosage, percentage of recommended dietary allowance (RDA), and ingredients. It is important to look for supplements that are free of artificial ingredients or preservatives, and, if necessary or desired, sugar or added sweeteners. Know the recommended dosage – 90 mg for healthy men and 75 mg for healthy women – and shop according to your needs. If you’re looking for something in pill form, Care/of’s Vitamin C, The Citrus Savior, is a high quality, easily digested formula that provides maximum absorption.

Groups of individuals that would benefit from taking vitamin C daily

The best source of vitamin C is a healthy diet packed with colorful foods including citrus fruit, Bell peppers, cruciferous vegetables like broccoli and brussel sprouts, tomatoes, strawberries and white potatoes. People who do not have a varied diet might be at risk for C deficiency, as well as smokers and those exposed to pollution or secondhand smoke. Age, overall health, and stress level are also possible factors in determining your need to supplement vitamin C.

Final takeaways

Vitamin C is essential to many critical functions in the human body. The good news is that most people can get adequate amounts of it in a healthy diet, especially when consuming fresh food at its peak ripeness. If you need more, supplementation is fairly simple and straightforward. As always, check with your physician or healthcare provider when exploring appropriate supplementation.

While there is widespread agreement among medical professionals as to the critical functions of vitamin C, its impact on more common conditions is up for grabs.

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