Vitamin C

Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Humans, unlike most animals, are unable to synthesize vitamin C endogenously, so it is an essential dietary component.

  • Vitamin C is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters; vitamin C is also involved in protein metabolism. Collagen is an essential component of connective tissue, which plays a vital role in wound healing. Vitamin C is also an important physiological antioxidant and has been shown to regenerate other antioxidants within the body, including alpha-tocopherol (vitamin E).
  • Ongoing research is examining whether vitamin C, by limiting the damaging effects of free radicals through its antioxidant activity, might help prevent or delay the development of certain cancers, cardiovascular disease, and other diseases in which oxidative stress plays a causal role.
  • In addition to its biosynthetic and antioxidant functions, vitamin C plays an important role in immune function and improves the absorption of nonheme iron, the form of iron present in plant-based foods.
  • Insufficient vitamin C intake causes scurvy, which is characterized by fatigue or lassitude, widespread connective tissue weakness, and capillary fragility
  • The total body content of vitamin C ranges from 300 mg (at near scurvy) to about 2 g. High levels of vitamin C (millimolar concentrations) are maintained in cells and tissues, and are highest in leukocytes (white blood cells), eyes, adrenal glands, pituitary gland, and brain. Relatively low levels of vitamin C (micromolar concentrations) are found in extracellular fluids, such as plasma, red blood cells, and saliva.


In 2017, a ground-breaking study was published lead by Paul Marik showing that Vitamin C, hydrocortisone, and thiamine delivered quickly after hospitalization, reduced mortality by around 87%.1)

  • As of March 22, 2022, this study is being challenged as, “indeed research fraud and the data is fabricated,” by Dr. Kyle Sheldrick.2)
  • Sun-Young Jung and colleagues found a decrease in hospital mortality associated with patients treated for sepsis in South Korean hospitals. This association was pronounced in the elderly with multiple comorbidities, pneumonia, septic shock, and mechanical ventilation.4)
  • Tomoko Fujii and colleagues found no benefit to the addition of Vitamin C and thiamine to hydrocortisone.5)
    • The multi-national aspect of the study leaves open the possibility of a Simpson's paradox not accounted for by the authors.
    • The study focused specifically on patients suffering Sepsis-3.
January 5, 2022 | Sun-Young Jung et al | Critical Care (Journal) | Vitamin C for ≥ 5 days is associated with decreased hospital mortality in sepsis subgroups: a nationwide cohort study | DOI
January 17, 2020 | Fujii et al | JAMA | The VITAMINS Randomized Clinical Trial | JAMA. 2020;323(5):423-431. doi:10.1001/jama.2019.22176