Best vitamin C supplements

While walking through the drug store vitamins aisle, you might be tempted to stock up on the vitamins that you've heard are essential and beneficial to your health. Despite what you may have heard about taking vitamin C, people often get enough in the food they eat. For example, from eating citrus and other kinds of fruits that have high vitamin C content. So using a supplement might not be useful, except in cases of a vitamin C deficiency or scurvy (Stephen, 2001).

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Gummies, capsules, a carbonated drink mix—there are many different forms of vitamin C that have varying ingredients, different amounts of vitamin C, and even unique directions. These products are sold as supplements, so they are not regulated or evaluated by the FDA. As such, they are not intended to treat, prevent, or cure a disease.

The Institute of Medicine recommends that the average healthy adult needs about 100 mg of vitamin C a day. This requirement is often met by a diet that's rich in fruits and vegetables. In fact, researchers reported that you could get more than enough vitamin C by eating five varied sources of fruits and vegetables a day. Citrus, strawberries, kiwi, and peppers are excellent sources of vitamin C (NIH, 2020).

Vitamin C pills 

Vitamin C pills often contain 500-1000 mg of l-ascorbic acid, though even higher doses can be found. They are marketed as a dietary supplement for adults. The directions on most of these are to take once daily with meals. Some versions of Vitamin C pills contain l-ascorbic acid alone, while others might contain a combination of vitamins and electrolytes. There are also chewable forms of vitamin C available in similar dose ranges.

Vitamin C gummies

Vitamin C gummies are sold under a few popular brands and usually contain between 250-750 mg of ascorbic acid. The directions for these products often vary, so talk to your healthcare provider about dosing vitamin C gummies and follow the advice they give you. Of note, a small study done in thirty male patients found that the absorption of vitamin C from pills and gummies was similar, and researchers concluded that adults could use either for supplementation (Evans, 2019).

Vitamin C powder

Vitamin C powder, otherwise known as ascorbic acid powder, often contains a combination of vitamins and minerals advertised to give your immune system a boost. The most common vitamin C powder packets include 1000 mg of vitamin C, several B vitamins, zinc, calcium, and magnesium. Because of the addition of calcium and magnesium, this supplement has a higher risk of interacting with other medications you take. Taking two medicines that can interact can lead to potentially harmful side effects, so talk to your healthcare provider before starting ascorbic acid powder.

Vitamin C is an essential part of your wellness. It plays many roles in your health, including (Carr, 2017):

• Fighting infections

• Healing wounds

• Synthesizing necessary chemicals for your brain called neurotransmitters

• Helping your body form an essential structural protein called collagen

• Acting as an antioxidant against free radicals

People who have a low intake of vitamin C can develop dry skin, become very tired, and eventually can develop a disease known as scurvy. While scurvy is very rare in developed countries, vitamin C is actually the indicated treatment for it (Stephen, 2001). But vitamin C is not recommended as a supplement in people who get enough through their diet.

A reason for this is the lack of compelling evidence for using it to treat or prevent disease­. Let's start with the common cold. A review published in 2013 compiled all available clinical data on using vitamin C for the common cold. After analyzing a total of 11,306 patients, the authors reported that supplementing with vitamin C did not lower the incidence of colds. However, the duration of symptoms was reported to be 8% shorter in adults and 14% shorter in children who took a vitamin C supplement (Hemilä, 2013).

Another review studied the use of vitamin C supplements for the prevention of heart disease. Researchers reported no significant impact on cardiovascular disease rate between the group who got high doses of vitamin C and the placebo group (Al-Khudairy, 2017).

There are possible side effects of taking too much vitamin C, so always use these products as directed by your healthcare provider. These side effects are pretty rare and often not very serious. A few side effects of taking too much vitamin C include diarrhea, dizziness, fatigue, headache, and nausea (Padayatty, 2010). There are also case reports of vitamin C causing a build-up of uric acid which can lead to kidney stones (Abdullah, 2020). 

Vitamin C should not be given to those who have a deficiency of an enzyme called G6PD (Abdullah, 2020). Deficiency in G6PD is more common amongst men of African and Mediterranean descent and can impact the way your blood cells fight off certain toxins. 

Because of the combination of vitamins and electrolytes in some vitamin C powders and in multivitamins, these can 'interact' with other medications. A drug interaction is when one medicine impacts the absorption or metabolism of another. Taking two medicines that interact can lead to potentially serious side effects.

The magnesium in some vitamin C powders can have a potentially harmful interaction with a drug used to treat HIV, Raltgegravir (and others). Talk to your doctor about starting a new supplement if you take any medications daily.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

February 11, 2021

Written by

Amro Alhelawe, PharmD

Fact checked by

Steve Silvestro, MD

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About the medical reviewer

Steve Silvestro, MD, Ro

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.