Vitamin C Does Speed Up COVID Recovery

A study published recently in the Journal of the American Medical Association (JAMA) shows that 8 grams of vitamin C reduces duration of symptoms from mild COVID-19 infection by 18%. The study involved 219 people either given standard care, or vitamin C (8 grams), or zinc (7mg) or both vitamin C and zinc.

So this was a trial to see if vitamin C or/and zinc could speed up recovery. and hence reduce the duration of symptoms. Those taking vitamin C, with or without zinc, reached a halving of symptom severity, which was the trial’s criteria, 1.2 days sooner (after 5.5 days) compared to standard treatment (after 6.7 days).

Now, here’s the twist. The authors state that there was no statistical significance between the groups. This is not true. Professor of Public Health Harri Hemila, from the University of Helsinki calculated “the rate of recovery in the vitamin C group compared to the standard of care group and found that vitamin C significantly increased the rate of recovery. – by a statistically significant 71%. This is different to the reduced average duration of 18% and relates to how many recover each day.  “This direct comparison of recovery rate between the vitamin C and the standard of care groups was not published by Thomas et al.” he says.

In the graph below, where the vertical axis, at 100%, is the measured point of recovery, and the horizontal axis is the number of days, that more in the vitamin C group are recovering from the first measuring day, day 4 up to day 10 seen as the orange line (vitamin C) and blue (control) lines diverging. Then, on day 10 the vitamin C was stopped and the lines increasingly converge. becoming little different by day 16. This pattern is entirely consistent with the positive effect of vitamin C.

Recovery Vit C and Covid Graph

He points out that “A dose-response effect for vitamin C on common cold duration has also been indicated [from previous studies], with a prediction that 6-8 g/day doses might shorten viral upper respiratory infections by some 20% . This prediction is consistent with the 18% effect observed by Thomas et al. with the dosage of 8 g/day. Furthermore, there are indications [in other studies] that vitamin C might also have effects on more serious infections caused by SARS-CoV-2.”

This is not the first time JAMA has misled its readers about vitamin C, he says in his critique, citing five other examples. JAMA’s anti-vitamin/pro-drug commentary further compounded this misinformation with statements such as “these 2 supplements failed to live up to their hype.” Was this an intended hatchet job? The authors were told of this incorrect statistical analysis prior to publication so I think we have to conclude yes and one that will cost lives.

There are, in my opinion, three other major problems with this study, the last relating to the zinc supplementation.

1. The study, which was meant to involve 500 people, and was erroneously stopped early, contradicting their study design criteria. If they had continued the positive effect observed may have been further strengthened.

2. The other issue, which most practitioners experienced with vitamin C therapy know, and is supported by previous studies, is that the positive effect of vitamin C is strongest in those who start on the first day of infection or in studies giving continuous supplementation and therefore the participants would be supplementing during the first day of infection. Vitamin C tends to not work so well once a viral infection has taken hold.

I asked the study author, Dr Milind Desai regarding the number of days that infection had occurred prior to starting vitamin C. He told me “How many days they were symptomatic [prior to treatment] was recorded but obviously difficult to ascertain. This data is not available.” I’m not sure why it is difficult to ascertain, or unavailable, because all results in this trial were based on self-reports and asking when your symptoms start is a basic question in any medical examination and duly recorded, as he stated it was. Also, since only those testing PCR positive were included one imagines there is some delay in getting symptoms, getting PCR tested, then getting started on this trial which the author said happened “on or around the first day of presentation to the outpatient setting.” Given that the importance of the timing of any medication in a disease cycle this should have been reported or, at least, listed as a weakness in the study. Starting vitamin C supplementation earlier in the disease cycle would be expected to improve the effectiveness.

The daily dosage of 8 grams of ascorbic acid taken 2/3 times a day, is a sensible dose to trial. Anderson et al showed that 46% of those taking 8 grams during the first day of infection were symptom-free within 24 hours. Linus Pauling also made this point – that vitamin C must be taken from the very first signs of infection although he advocated a higher dose – 1 gram an hour.

The study also reported a higher incidence of nausea, diarrhoea and stomach cramps in the vitamin C groups. This occurred in about one in ten. In this study most people were taking 4 g twice a day. If you take less more often, eg 1g every three hours, this also helps. For those who experience gastrointestinal effects the general clinical advice is to lower your dose of vitamin C up to your ‘bowel tolerance’. Gastrointestinal symptoms are thought to occur as a result of having more vitamin C in the lower gut that the body can absorb. Low stomach acid levels may also contribute to less vitamin C tolerance since its absorption is aided by an acid medium. This is not a major issue. The same occurs with many medications including antibiotics.

3. Regarding zinc, the dose of zinc at 7mg is a tenth of that shown to reduce duration of colds, namely 70mg, in other studies. These studies were referred to in the rationale – then ignored in the study design. So this dose may simply be too low. No other studies have shown reduced duration of infection at this dose. So, I’d ignore the finding in relation to zinc.

In summary, JAMA have allowed a distorted study write-up to imply that a) vitamin C and zinc don’t work and b) could be dangerous. This has been press released and the anti-vitamin media have jumped on it. The Daily Mail, for example, reported “Vitamin C and zinc WON’T help you fight off Covid – even in high doses – study reveals. Findings were so unimpressive scientists decided to call it off altogether. High doses even caused side effects including nausea, diarrhea and cramps.”

This study was rejected by the first journal it was presented to due to these critiques – but then not addressed and published as is.

Please support and sign the petition to stop this misinformation at

This is the link to the study:

And Prof Hemila’s critique: