Medical Matters > Treatment: High-dose Vitamin C

ME Essential Summer 2020


I have read about the use of high dose vitamin C injections being used to treat people with coronavirus infection. Could this also be used to treat ME?


In our current state of knowledge I would not recommend the use of high-dose vitamin supplements, including Vitamin C, as a treatment for ME/CFS. Taking high doses of vitamin C can also cause a number of side effects:

  • Diarrhoea
  • Nausea
  • Vomiting
  • Heartburn
  • Abdominal cramps
  • Headache
  • Insomnia

There is no reliable evidence to indicate that people with ME/CFS have vitamin deficiencies (with the exception of vitamin D) and no evidence from clinical trials to indicate that vitamins are a safe and effective form of treatment. The situation regarding the use of intravenous Vitamin C as a possible treatment for Covid-19 remains very speculative and unproven.

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Medical Matters is for information purposes only. The answers provided by Dr Shepherd and the ME Association’s other expert advisers should not be construed as medical advice. We recommend that any information you deem relevant is discussed with your GP as soon as possible. It is important to obtain advice from a GP who is in charge of your clinical care, who knows you well, and who can consider other likely causes for symptoms. Seek personalised medical advice whenever a new symptom arises, or an existing symptom worsens. Don't assume that new or worsened symptoms are a result of having ME/CFS.

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