Can I Take Vitamin C And D Together

  • 1st Revision: Tan Jit Yih


When you look at your average multivitamin supplement, you will find that both vitamin C and D are often found there together; saying it is okay to be taken together, along with all the other vitamins in there. Your body requires 13 vitamins to support growth, development, and daily bodily functions. It is interesting to know that Dr Anthony Fauci (director of the National Institute of Allergy and Infectious Diseases in the U.S.A.) recommends taking vitamin C and D supplements, as he does so himself.1 

Role of vitamin C

Vitamin C (or ascorbic acid, the synthetic form) plays an important role in the maintenance and normal functioning of the immune system and has been used in preventing and treating infections for almost a century now. Vitamin C is naturally found in citrus and other fruits and vegetables, and it is best known to be used in the prevention and treatment of scurvy

Vitamin C is also essential for the formation of collagen (the most abundant protein in your body!), tissue repair and the enzymatic production of a few neurotransmitters.

It is also key for the functioning of certain enzymes and is a known antioxidant. It is an essential nutrient that must be consumed regularly to prevent a deficiency. 

Vitamin C is deemed to be perfectly safe in healthy individuals, mostly due to its high water solubility and rapid clearance of surplus levels by the kidneys.2

Symptoms of low vitamin C levels

What are the symptoms of low vitamin C?

Two of the earliest signs are fatigue and poor mood. While symptoms of feeling overly tired and irritable appear rapidly, you can make them go away just as easily (within 24-48h) by taking in some extra vitamin C.

As vitamin C is essential for producing collagen - which keeps your skin looking plump and healthy - when you have low levels, your skin will start to suffer with dry, (sun) damaged skin as a result. So a higher vitamin C consumption is associated with better skin quality.3

Poor collagen production also results in having weaker blood vessels. When you have weak blood vessels, you tend to bruise easily. This can cover large areas of your body or present as small, purple dots under the skin. Easy bruising is typically one of the first obvious signs of vitamin C deficiency.3

Additionally, slow collagen production will also slow down the healing of wounds as it interferes with tissue formation and thus repair. People with chronic non-healing leg ulcers are significantly more likely to have a vitamin C deficiency. In very severe cases, old wounds may even reopen!3

Since your joints also contain a lot of collagen-rich connective tissue, low levels of vitamin C can cause painful and swollen joints.4

Weak and brittle bones may also be a result of low vitamin C levels as it is important for bone formation. This is especially seen in children as they are still growing and developing.4

Gum tissues can also become weak and inflamed due to vitamin C deficiency, and they bleed easily as the blood vessels are weakened too. Eventually, teeth can even fall out!2,3,4

Vitamin C is an important nutrient for your immune system, so having low levels are linked to poor immunity and a higher risk of infection. In fact, many people with scurvy eventually die from another infection due to their badly performing immune systems.2,3,4

Furthermore, Vitamin C and iron deficiency often occur together as low levels of vitamin C reduces the absorption of iron from plant-based foods.2,3,4

How much vitamin C do you need? Adults (non-smoker) between the ages of 19 and 64 need 40 mg of vitamin C a day.3

Role of vitamin D

Vitamin D is paramount for keeping your bones strong and your muscles healthy. It helps regulate the amount of calcium and phosphate in the body and acts as a steroid hormone. It also helps regulate the immune responses of the body. Vitamin D is produced in your skin on exposure to ultraviolet sunlight, but it is also found in foods, like oily fish and eggs. Vitamin D is essential in the formation of healthy and strong bones in children.6

Symptoms of low in vitamin D levels

Deficiency of vitamin D has been associated with diseases such as rickets, osteomalacia, osteoporosis, cardiovascular diseases and skin diseases. First signs may include: fatigue, bone pain, muscle weakness, aches or cramps and changes in mood (depression).6,7 

How much vitamin D do you need?

Adults, including pregnant and breastfeeding persons, and children older than 1 year old , should consider taking a daily supplement of 10 micrograms of vitamin D from October to March.They should continue to do so if they have darker skin or do not get frequent sun exposure.

Babies from birth to 1 year of age: whether exclusively or partially breastfed should be given a daily supplement containing 8.5 to 10 micrograms of vitamin D. 

Infant formula fed babies do not need a vitamin D supplement unless they are receiving less than 500 ml of infant formula daily, as infant formula is fortified with vitamin D.6

Can you take both in vitamins together?

Since vitamin D is a fat-soluble vitamin, you should try to take it with a meal as it will require the fat in order to be absorbed by your body. Vitamin C is a water-soluble vitamin, thus is best absorbed on an empty stomach, although some may complain about experiencing cramps. The best advice is to take vitamin C before your meal and vitamin D with your meal, but there is no problem with having them both in your body at the same time, as no interactions have been reported. 8

What you should not take with vitamin C

As Vitamin C is a water-soluble vitamin , it will be excreted through your urine, as you cannot store it. Thus, if  you take in too much caffeine, it can cause you to urinate more frequently  and deplete your body of vitamin C. Drinks and food containing caffeine, such as coffee, tea, cola, and chocolate, can hinder your absorption of vitamin C.9

Certain medications, like aspirin, antibiotics, antacids, blood thinners and birth control pills, can also reduce the amount of vitamin C in your body.10 If you are taking any of these, you may want to consider taking a vitamin C supplement after speaking to your doctor. Smoking and stress can also use up vitamin C for antioxidative purposes. Nicotine was seen to reduce the effects of vitamin C.10,11

What you should not take with vitamin D

There are  a whole list of drugs that interfere with vitamin D absorption; however, your doctor can adjust your vitamin D dosage to correct for this malabsorption.

This list provided by the Mayo clinic includes, but is not limited to: antacids, diuretics, anticonvulsants, St. John’s wort, antiretrovirals, alcohol, antirejection medications (after organ transplant), barbiturates, stimulant laxatives, tobacco, corticosteroids and glucocorticoids, hydroxychloroquine, digoxin, digitalis, and rifampin.12,13,14

However, if you havehypercalcemia, you should avoid high doses of vitamin D.15


It is believed that low levels of vitamin C leaves you more vulnerable to infections. Therefore, every year when the ‘R’ is in the month, an extra intake of vitamin C is encouraged to help boost your immune system and to prevent infectious diseases. 

Please do not stop taking the supplements your healthcare provider has prescribed or recommended. However, if you do feel worried about whether you are getting sufficientvitamin C and/or D and are currently not taking any supplements, try making some changes to your lifestyle, such as eating fresh and healthy foods and spending some quality time outdoors.


  1. [Internet]. Dr. Fauci Takes Isolated Vitamin D and Synthetic Vitamin C – Doctors Research, Inc.; [cited 2022 Sep 19]. Available from:
  2. Cerullo G, Negro M, Parimbelli M, Pecoraro M, Perna S, Liguori G, et al. The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19. Front Immunol. 2020; 11:574029.
  3. Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K. Vitamin C–enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr [Internet]. 2017 [cited 2022 Sep 22]; 105(1):136–43. Available from:
  4. DePhillipo NN, Aman ZS, Kennedy MI, Begley JP, Moatshe G, LaPrade RF. Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries: A Systematic Review. Orthopaedic Journal of Sports Medicine [Internet]. 2018 [cited 2022 Sep 22]; 6(10):232596711880454. Available from:
  5. Vitamins and minerals - Vitamin C. [Internet]. 2017 [cited 2022 Sep 20]. Available from:
  6. Vitamin D. [Internet]. 2017 [cited 2022 Sep 20]. Available from:
  7. Rai V, Agrawal DK. Role of Vitamin D in Cardiovascular Diseases. Endocrinol Metab Clin North Am. 2017; 46(4):1039–59.
  8. [Internet]. [date unknown]. Available from:
  9. Does Caffeine Affect the Absorption of Vitamins or Minerals? LIVESTRONG.COM [Internet]. [cited 2022 Sep 22]. Available from:
  10. Vitamin C. Mayo Clinic [Internet]. [cited 2022 Sep 22]. Available from:
  11. Shorey-Kendrick LE, McEvoy CT, O’Sullivan SM, Milner K, Vuylsteke B, Tepper RS, et al. Impact of vitamin C supplementation on placental DNA methylation changes related to maternal smoking: association with gene expression and respiratory outcomes. Clin Epigenet [Internet]. 2021 [cited 2022 Sep 22]; 13(1):177. Available from:
  12. Vitamin D. Mayo Clinic [Internet]. [cited 2022 Sep 22]. Available from:
  13. Kupisz-Urbańska M, Płudowski P, Marcinowska-Suchowierska E. Vitamin D Deficiency in Older Patients-Problems of Sarcopenia, Drug Interactions, Management in Deficiency. Nutrients. 2021; 13(4):1247.
  14. Kota BP, Abdul MIM, Allen JD, Kalagara M, Roufogalis BD. Effect of vitamin D3 supplementation on the pharmacokinetics of digoxin - a pilot study: Role of vitamin D3 in P-gp-mediated drug interactions. Fundamental & Clinical Pharmacology [Internet]. 2012 [cited 2022 Sep 22]; 26(4):543–8. Available from:
  15. Tebben PJ, Singh RJ, Kumar R. Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment. Endocrine Reviews [Internet]. 2016 [cited 2022 Sep 22]; 37(5):521–47. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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IIona Kosten

Master of Science - (MS), Immunology and Infectious diseases, Vrije Universiteit Amsterdam (VU Amsterdam), Netherlands

Ilona has a BSc and MSc in Biomedical Sciences and a PhD in Immunology with a sweet spot for “all things allergy”.
She’s published a number of articles in peer reviewed journals ranging from skin and mucosa tissue engineering, immunoassays, DCs, LCs and T cells."

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