Vitamin C and Stress

Why you need more vitamin C when you're stressed

Did you know?

Most plants and animals synthesize their own vitamin C, and their internal production of vitamin C greatly increases when under stress. Humans, however, as well as guinea pigs, fruit-eating bats, and select primates are not able to produce vitamin C and must consume it in their diet. As has been noted, species who produce their own vitamin C greatly increase their production of this key nutrient when they are under stress. For example, an unstressed goat produces up to 13,000 mg of ascorbate a day, and a stressed goat can produce up to 13 times that much. Monkeys, our closest evolutionary relative, are routinely given 55 mg per kg of body weight per day of dietary vitamin C for health maintenance (1, 2, 3). This would translate into 3,250 mg a day of vitamin C for a 130-pound person, or 4,333 percent of the current RDA for vitamin C.

Why is more vitamin C produced under stress?

There are several reasons why animals produce more vitamin C when stressed. For one, vitamin C uses its antioxidant power to donate electrons to copper (Cu2+), which activates enzymes responsible for producing norepinephrine and dopamine. Norepinephrine is the main neurotransmitter in the sympathetic nervous system, and it is responsible for keeping us awake and alert, helping us retain information, and activating our fight-or-flight response. So, under prolonged periods of stress, when more norepinephrine is produced, we need more vitamin C to keep these enzymes active.

stress response system


In fact, a 2017 study found that out of 44 critically ill patients who were receiving the minuscule government recommended intake of vitamin C, 75% had abnormally low plasma vitamin C levels, and one-third were fully deficient in vitamin C (4). When ill or challenged by infection, vitamin C is quickly depleted and the need for this important antioxidant dramatically increases.

Vitamin C is concentrated in the white blood cells of the immune system and is there to serve us at times of illness or pathogen invasion (5). For example, studies show that vitamin C is quickly depleted with severe infections and especially in sepsis (6). Because of this, vitamin C supplementation may better prepare the body to deal with viral infections or other severe illnesses that stress the immune system.

In fact, high-dose intravenous vitamin C has been successfully used in the treatment of about 50 COVID patients in China, all of whom saw real-time improvements in oxygenation, and a 3 to 5 day shorter hospital stay compared with those who didn’t receive IV-C (7).

Vitamin C and Anxiety + Mood

Vitamin C, the potent antioxidant that it is, has been studied in relation to anxiety, depression, and mood, as well as its relationship with perceived stress. Could vitamin C status have an impact on the stress we feel? Well, this seems to be true in guinea pigs, who also cannot produce their own vitamin C. In fact, scientists found that guinea pigs who are deficient in vitamin C hyper-secrete the stress hormone cortisol (8). Human studies seem to show a similar relationship between vitamin C and stress.

In humans, healthy young adults who supplemented with 1,000 mg vitamin C, three times a day (total of 3g/day), were able to better respond to psychological stressors like public speaking, as measured by less increase in blood pressure, and faster decreases in salivary cortisol, and lower subjective stress (9).

In high school students, those who supplemented with 500 mg vitamin C per day for 14 days showed decreased anxiety levels as measured by Beck Anxiety Inventory scores, compared with their scores prior to the intervention (10).

In patients with type-2 diabetes, a group assigned to supplement with 1,000 mg/day of vitamin C for 6 weeks had significantly decreased anxiety levels compared those taking either vitamin E or a placebo (11).

As we see in these studies, having plenty of vitamin C sets our bodies up to respond to stress efficiently, and may even decrease our feelings of stress and anxiety. This makes sense when we look at vitamin C’s role in the stress response. As mentioned earlier, we need vitamin C to produce our fight-or-flight hormone, norepinephrine. Our adrenal glands also require vitamin C to produce other stress hormones, like cortisol. In fact, studies have shown that as we produce more cortisol (in long-term or acute stress) we also use more vitamin C (12).

Vitamin C: Essential for More Than Immunity

Learning that vitamin C may play a role in modifying our response to stress and anxiety is a great wake-up call. This reminds us of the importance of optimizing our nutrition status. In particular, we should keep an eye on building our antioxidant reserves.

Vitamin C is absolutely essential for our health, and every day we learn more about its many functions that go well beyond bolstering immunity or allowing for healthy collagen production.

One great way to help ourselves thrive amid all the modern stressors of today is to increase our vitamin C intake. A diet high in fresh fruits and vegetables is a great start, but here at Alkaline for Life we have found that most of us benefit from substantial supplementation with ascorbate/vitamin C. And of course, a wise person wants the purest most potent form of ascorbate vitamin C that is fully reduced and fully buffered.




  1. National Research Council (US) Subcommittee on Laboratory Animal Nutrition. 1995. Nutrient Requirements of Laboratory Animals: 4th Revised Edition. National Academies Press (US), Washington, D.C.
  2. Chatterjee, I. B., et al. 1975. Synthesis and some major functions of vitamin C in animals. Annals of the New York Academy of Sciences 258:24–47. doi:10.1111/j.1749-6632.1975.tb29266.x.
  3. Stone, I. 1979. Homo sapiens ascorbicus, a biochemically corrected robust human mutant. Medical Hypotheses 5(6):711–21. doi:10.1016/0306-9877(79)90093-8.
  4. Carr, A. C., et al. 2017. Hypovitaminosis C and vitamin C deficiency in critically ill patients despite recommended enteral and parenteral intakes. Critical Care (London, England) 21(1):300. doi:10.1186/s13054-017-1891-y.
  5. Lahiri, S., and B. B. Lloyd. 1962. The effect of stress and corticotrophin on the concentrations of vitamin C in blood and tissues of the rat. The Biochemical Journal 84(3):478–483. doi:10.1042/bj0840478.
  6. Marik, P. E. 2018. Vitamin C for the treatment of sepsis: The scientific rationale. Pharmacology & Therapeutics 189:63–70. doi:10.1016/j.pharmthera.2018.04.007.
  7. Anderson, P. S. 2020. Intravenous ascorbic acid for supportive treatment in hospitalized COVID-19 patients. Journal of Orthomolecular Medicine 35(1).
  8. Enwonwu, C. O., et al. Effect of marginal ascorbic acid deficiency on saliva level of cortisol in the guinea pig. Archives of Oral Biology 40(8):737–742. doi:10.1016/0003-9969(95)00030-s.
  9. Brody, S., et al. A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress. Psychopharmacology 159(3):319–324. doi:10.1007/s00213-001-0929-6.
  10. de Oliveira, I. J. L., et al. 2015. Effects of oral vitamin C supplementation on anxiety in students: A double-blind, randomized, placebo-controlled trial. Pakistan Journal of Biological Sciences: PJBS 18(1):11–18. doi:10.3923/pjbs.2015.11.18.
  11. Mazloom, Z., et al. 2013. Efficacy of supplementary vitamins C and E on anxiety, depression and stress in type 2 diabetic patients: A randomized, single-blind, placebo-controlled trial. Pakistan Journal of Biological Sciences: PJBS 16(22):1597–1600. doi:10.3923/pjbs.2013.1597.1600.
  12. Padayatty, S. J., et al. 2007. Human adrenal glands secrete vitamin C in response to adrenocorticotrophic hormone. The American Journal of Clinical Nutrition 86(1):145–149. doi:10.1093/ajcn/86.1.145.