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  • Writer's pictureDr. Brian Lum

What Form Of Vitamin C Is Best?

Vitamin C supplementation, particularly when there is a vitamin C deficiency, can be very helpful for patients.  The information below is intended to make the choosing process a little less confusing. 

Like everything in our practice, there are no fixed rules for everyone, and there is no single form of vitamin C for every ailment. A supplement should be selected with the same care a doctor would take when selecting a pharmaceutical. 

Supplements can be very powerful, and using them in the right form at the right time at the right dose is imperative to achieve the desired outcome.

Purity and quality also matter - poor quality or contaminated supplements can cause additional health problems or be completely ineffective. 

As always, work with a doctor when changing or adding medication or supplementation. 

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The Many Uses of Vitamin C

There are a wide variety of uses of supplemental vitamin C that are supported by the latest medical research; the most common is to mitigate the severity of the common cold. Vitamin C supplementation has also has been used for things as varied as to decrease mortality in patients with septic shock and to prevent atrial fibrillation in high-risk patients. [1] [2]

Regular vitamin C supplementation has been shown to reduce by half the incidences of common cold symptoms in individuals under acute physical stress. [3] For those interested, the third citation explores why there is still a widespread bias against the use of vitamin C in mainstream medicine despite its scientific validity. 

Vitamin C is a crucial component of a properly functioning immune system and functions as an antioxidant (a chemical that neutralizes free radicals) and is a cofactor for essential enzymes. In certain cases, there are optimal forms of the vitamin for an individual.   

Vitamin C deficient patients who do not tolerate traditional vitamin C supplementation and who do not get enough from food sources can take a different form to correct their deficiency. 

Form: Ascorbic Acid

This is a common form of vitamin C you will find in many supplements. It is also the form that is used in most scientific studies. The anti-cancer, antioxidant, and anti-viral benefits of ascorbic acid are well documented. [4]

Chronic illnesses and neurological disorders can be prevented by vitamin C supplementation in certain circumstances. [5] Ideally, you would get all your vitamin C from your diet, but supplementing with this form would also suffice. 

Ascorbic acid can irritate a sensitive digestive system.  Some patients, like those suffering from the effects of mold exposure, find that they cannot take ascorbic acid in a supplement because it causes them an array of symptoms - some of which can include nausea, stomach pain, digestive problems, anxiety, insomnia, or migraines. 

In these cases, I work with patients to find a form they can tolerate.

Form: Calcium Ascorbate or ‘Ester C’

This form of vitamin C has a neutral pH, unlike ascorbic acid. This can make it gentler on the digestive system for some. 

Ester C supports your immune system and can improve allergy symptoms by reducing histamine levels - Ester C with bioflavonoids (particularly quercetin) can be helpful to decrease histamine in the body.  Patients should only take Ester C with added bioflavonoids if advised to do so by their doctor because it can be irritating to their digestive system. 

Ester C is better retained in tissues and less quickly excreted than ascorbic acid. [6] It can, therefore, be a good source for those who have trouble ‘keeping up’ their vitamin C levels, as it can also be taken long-term.  

Form: Liposomal Vitamin C

This form is the best absorbed and is great for those with digestive problems because it can be absorbed without fully going through the digestive system. It has also been shown to be more bioavailable than non-liposomal varieties. [7]

Liposomal vitamin C is often made with sunflower lecithin, which can help the liver detoxify the body.

For those with methylation (detoxification) issues, like those who are heterozygous or homozygous for the MTHFR gene, liposomal vitamin C can assist in methylation.

For those with severe deficiencies, this is sometimes the best option because there can be gut malabsorption component in those with long-term vitamin C deficiencies. 


Working with a functional medicine doctor is important in choosing the right combination of treatments that work for you as even the choice of a vitamin can be fraught with difficulty for those who are very sensitive.

For many with a persistent sore throat or those dealing with the flu, the addition of rose hip tea to Ester-C and zinc picolinate can provide fast relief and symptom alleviation. For some patients looking to support wound healing, Ester C and liposomal vitamin C could work synergistically to help heal them faster.

There are as many combinations of treatments as there are unique individuals - always remember that what works for one person may not work for you.

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These are very loose guidelines and should not be used to diagnose or treat yourself.

Always be cautious when hearing about a single supplement that is 'good for everything' - specificity is the key when administering any medication or supplement.  

Always work with a doctor to develop a plan that considers your current health status, recent testing, and any medical conditions you may have.

I am currently accepting new patients and offer online consultations worldwide.

If you would like to schedule a free 15 minute consultation with me to ask questions about becoming a patient click the link below.


Written by Stephanie Lum and Dr. Brian Lum

Disclaimer: If you think that you may have a medical emergency, call your doctor or 911 immediately. No action or inaction should be taken based solely on the contents of this information. Nor should you ever delay seeking medical advice or treatment due to the information contained on this Website. The information on this Website is not intended to diagnose, treat, cure, or prevent any disease or medical condition. The information discussed is not intended to replace the advice of your healthcare provider. Reliance on the information provided by this Website, Dr. Brian Lum, or Functional Healthcare Institute is solely at your own risk.


[1] Zabet, M.H.; Mohammadi, M.; Ramezani, M.; Khalili, H. Effect of high-dose ascorbic acid on vasopressor’s requirement in septic shock. J. Res. Pharm. Pract. 2016, 5, 94–100. 

[2] Hemilä, H.; Suonsyrjä, T. Vitamin C for preventing atrial fibrillation in high risk patients: A systematic review and meta-analysis. BMC Cardiovasc. Disord. 2018, 17, 49. 

[3] Hemilä, Harri, and Elizabeth Chalker. 2022. "Bias against Vitamin C in Mainstream Medicine: Examples from Trials of Vitamin C for Infections" Life 12, no. 1: 62.

[4] Ali, Anwar, Sakhawat Riaz, Waseem Khalid, Maleeha Fatima, Umber Mubeen, Quratulain Babar, Muhammad Faisal Manzoor, Muhammad Zubair Khalid, and Felix Kwashie Madilo. “Potential of Ascorbic Acid in Human Health against Different Diseases: An Updated Narrative Review.” International Journal of Food Properties 27, no. 1 (2024): 493–515. doi:10.1080/10942912.2024.2327335.

[5]  Ali, Anwar, Sakhawat Riaz, Waseem Khalid, Maleeha Fatima, Umber Mubeen, Quratulain Babar, Muhammad Faisal Manzoor, Muhammad Zubair Khalid, and Felix Kwashie Madilo. “Potential of Ascorbic Acid in Human Health against Different Diseases: An Updated Narrative Review.” International Journal of Food Properties 27, no. 1 (2024): 493–515. doi:10.1080/10942912.2024.2327335.

[6]Mitmesser, Susan H., Qian Ye, Mal Evans, and Maile Combs. 2016. “Determination of Plasma and Leukocyte Vitamin C Concentrations in a Randomized, Double-Blind, Placebo-Controlled Trial with Ester-C.” SpringerPlus 5 (1): 1161–1161.

[7] Gopi, Sreerag, and Preetha Balakrishnan. 2021. “Evaluation and Clinical Comparison Studies on Liposomal and Non-Liposomal Ascorbic Acid (vitamin C) and Their Enhanced Bioavailability.” Journal of Liposome Research 31 (4): 356–64.


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