Health & Wellness Vitamin C [Ascorbic Acid, Ascorbate]

Does Vitamin C really reduce cortisol?

Muscluar Runner

Vitamin C or Ascorbic Acid is involved in a number of biochemical pathways that are important for the health of exercising individuals [1]. Cortisol is steroid hormone released in response to physical or mental stress [2] and is also known as the archenemy of bodybuilders. Its main function is to increase blood sugar (glucogenesis) [3]; it counteracts insulin. Cortisol also suppresses immune system, decreases bone formation and it aids in fat, protein and carbohydrate metabolism. [3]

Can vitamin C attenuate cortisol secretion?

Several studies with runners competing in prolonged running have shown that ingesting vitamin C attenuated post-race serum cortisol concentration [4-6]. However, carbohydrate intake in these subjects was not controlled and they were not randomized to treatment groups. Carbohydrate ingestion during prolonged and intense exercise is associated with higher plasma glucose levels and attenuated cortisol response [7,8].

David C. Nieman and others [9] wanted to improve previous studies with randomizing subject into treatment groups and by carefully measuring carbohydrate intake. The results of this study considerably different from the previous studies. Plasma ascorbic acid was significantly higher (and rose more during the race) in the vitamin C compared with placebo. Serum cortisol was strongly elevated in both groups but surprisingly significantly greater elevation was measured in the vitamin c group.

Several explanations are possible. In previous studies subjects were not randomized to treatment groups and carbohydrate intake during race were ad libitum and retrospectively estimated.[9]

If you are looking for alternative ways to reduce cortisol, please check out our post on ashwagandha extract or phosphatidylserine


  1. Peake, Jonathan M. “Vitamin C: effects of exercise and requirements with training.” International journal of sport nutrition and exercise metabolism 13.2 (2003): 125.
  2. Rosmond, Roland, Mary F. Dallman, and Per Björntorp. “Stress-related cortisol secretion in men: relationships with abdominal obesity and endocrine, metabolic and hemodynamic abnormalities.” Journal of Clinical Endocrinology & Metabolism 83.6 (1998): 1853-1859.
  3. Marieb, Elaine Nicpon, and Katja Hoehn. Human anatomy & physiology. Pearson Education, 2007.
  4. Nieman, David C., et al. “Influence of vitamin C supplementation on cytokine changes following an ultramarathon.” Journal of Interferon & Cytokine Research 20.11 (2000): 1029-1035.
  5. Peters, E. M., et al. “Vitamin C supplementation attenuates the increases in circulating cortisol, adrenaline and anti-inflammatory polypeptides following ultramarathon running.” International journal of sports medicine 22.7 (2001): 537-543.
  6. Peters, E. M., R. Anderson, and A. J. Theron. “Attenuation of increase in circulating cortisol and enhancement of the acute phase protein response in vitamin C-supplemented ultramarathoners.” International journal of sports medicine 22.02 (2001): 120-126.
  7. Nieman, David C., et al. “Cytokine changes after a marathon race.” Journal of Applied Physiology 91.1 (2001): 109-114.
  8. Nieman, David C., et al. “Influence of mode and carbohydrate on the cytokine response to heavy exertion.” Medicine and science in sports and exercise 30.5 (1998): 671.
  9. Nieman, David C., et al. “Influence of vitamin C supplementation on oxidative and immune changes after an ultramarathon.” Journal of Applied Physiology 92.5 (2002): 1970-1977.