Feasibility of Vitamin C in the Treatment of Post Viral Fatigue with Focus on Long COVID, Based on a Systematic Review of IV Vitamin C on Fatigue.

Nutrients. 2021;13(4)
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Plain language summary

Fatigue often occurs as a symptom of severe diseases. It is currently coming into focus as a major symptom of long COVID. The aim of this study was to provide a feasibility analysis of whether the use of intravenous (IV) vitamin C in post-viral fatigue, particularly after COVID-19, should be further investigated. This study is a review which included nine clinical studies compromising of 720 participants. Three of the four randomised-controlled trials showed a significant decrease in fatigue in patients having high-dose vitamin C compared to their controls. Similarly, four of the five observational studies observed a significant reduction in fatigue. Authors conclude that the effects of IV vitamin C on post-viral COVID-19 fatigue should be investigated in clinical trials.


Fatigue is common not only in cancer patients but also after viral and other infections. Effective treatment options are still very rare. Therefore, the present knowledge on the pathophysiology of fatigue and the potential positive impact of treatment with vitamin C is illustrated. Additionally, the effectiveness of high-dose IV vitamin C in fatigue resulting from various diseases was assessed by a systematic literature review in order to assess the feasibility of vitamin C in post-viral, especially in long COVID, fatigue. Nine clinical studies with 720 participants were identified. Three of the four controlled trials observed a significant decrease in fatigue scores in the vitamin C group compared to the control group. Four of the five observational or before-and-after studies observed a significant reduction in pre-post levels of fatigue. Attendant symptoms of fatigue such as sleep disturbances, lack of concentration, depression, and pain were also frequently alleviated. Oxidative stress, inflammation, and circulatory disorders, which are important contributors to fatigue, are also discussed in long COVID fatigue. Thus, the antioxidant, anti-inflammatory, endothelial-restoring, and immunomodulatory effects of high-dose IV vitamin C might be a suitable treatment option.

Lifestyle medicine

Fundamental Clinical Imbalances : Immune and inflammation
Patient Centred Factors : Triggers/Intravenous Vitamin C
Environmental Inputs : Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Journal Article ; Systematic Review


Nutrition Evidence keywords : Vitamin C ; Body weight ; Body mass index ; Fatigue