Update on vitamin D for covid

Sun face mask vitamin D covid

A few months back I wrote an article about the only randomized controlled trial that had at that point been done on vitamin D as a treatment for covid. That trial, which was carried out in Spain, showed very impressive results. There was an incredible 96% reduction in the relative risk of requiring ICU treatment among those treated with 25-hydroxyvitamin D (an activated form of vitamin D).

Unfortunately, that study had some significant flaws. It was small, with only 76 patients in total, and it was open-label, meaning that both the doctors treating the patients and the patients themselves knew who was in which group. These two flaws mean there are lots of different ways in which the trial could have ended up showing an impressive result that isn’t real.

Since then, two more randomized controlled trials of vitamin D for covid have posted their results. The first study was published in the Post-Graduate Medical Journal in November 2020. This was a double-blind randomized controlled trial carried out at a hospital in India. The authors did not receive any specific funding for their work, and reported no conflicts of interest.

Healthy patients who were admitted to the hospital with asymptomatic or mildly symptomatic covid were eligible to be included in the study.

Why were they admitting people who were only mildly symptomatic?

Why were they admitting people who were completely asymptomatic?

Are there so many hospital beds available in India that they admit people who are completely healthy?

I don’t know, it seems very strange to me.

Apparently the only requirement to be admitted to the hospital was a positive covid PCR test, which for unclear reasons was taken from healthy people who weren’t showing any symptoms. This is odd, and it limits the validity of the study, because the probability increases that a large proportion of those being admitted to hospital will be false positives, and not really covid patients at all. Obviously, this will make it harder to find any meaningful clinical effect of a treatment.

Apart from being healthy and having a positive covid PCR test, potential participants also had to have vitamin D deficiency, which they defined as a level of circulating 25-hydroxyvitamin D in the blood of less than 20 ng/ml. This part kind of makes sense. A previous study I’ve written about found a huge reduction in respiratory infections in people with low vitamin D levels who were treated with vitamin D supplements, while there was a much smaller effect in people who had decent levels in the blood to begin with.

It’s reasonable to think that people with a deficiency would be the ones to benefit most from treatment with vitamin D, so from that perspective it makes sense to check vitamin D levels before treating. On the other hand, if vitamin D is shown to be effective against covid, then in the real world doctors probably aren’t going to check the vitamin D levels of patients before they start treating them – they’re just going to give them the vitamin D. So adding this requirement makes the study less applicable to the real world.

After inclusion in the study, patients were randomized to receive either 60,000 IU of vitamin D per day (1,500 mcg), or a matching placebo. In total, 40 patients were recruited in to the study. Of these, 16 received vitamin D and 24 received the placebo. Yes, I agree, 40 is a very small number. Yes, the odds that this study will be able to detect a meaningful difference, even if one does exist, are small at best.

Unfortunately, the researchers topped things off by choosing a completely meaningless endpoint for the study. They chose to look at the amount of time it takes for patients to have a negative PCR test. Patients don’t care about whether they are still positive on a PCR swab or not (at least, I imagine they don’t). They care about whether they feel sick or not, and about how much time they need to spend in hospital, and about whether they live or die, and whether they have complications. Unfortunately the researchers didn’t gather any data on symptoms or anything else that actually matters to patients, so that data isn’t even available for us to analyze.

Let’s get to the results. On average, patients in the vitamin D group became PCR negative at 18 days after inclusion in the study. Patients in the control group also became PCR negative at 18 days. So, there was no difference between the groups.

Would I have expected a difference? No. A study that only has 40 participants, and that chooses to only recruit people with disease ranging from mild to non-existent, is almost certain to fail to find any meaningful effect. This was a very low quality study.

Let’s move on to study number two. This one hasn’t yet been peer-reviewed, and is currently only available as a pre-print at MedRxiv. It was a double-blind randomized controlled trial involving 240 patients. So, so far, it ticks all the important boxes for quality. Unlike the Spanish study, this one was double-blind. And unlike both the Spanish and the Indian study, this one was also quite large. In fact it was more than twice as large as both the other two studies put together.

So, just from this limited information, we know that this is the highest quality study yet that looks at vitamin D as a treatment for covid. The study was carried out in Brazil, and was funded by the Brazilian government and by the state of Sao Paolo. The authors reported no conflicts of interest.

In order to be included in to the study, participants had to be over the age of 18 and have covid, as diagnosed either by PCR or a CT-scan of the chest. They also had to have symptoms that were severe enough to require hospitalization, or risk factors for more serious disease, such as diabetes, heart disease, cancer, or obesity. So far so good – they were looking primarily at people who were quite sick, or at least at increased risk of becoming quite sick. Those are the people we want to find an effective treatment for. The researchers excluded people who had previously supplemented with vitamin D, presumably to increase the odds of getting a significant result.

Participants were split evenly between the intervention group and the placebo group. Those in the intervention group received a single bolus containing 200,000 IU of vitamin D (5,000 mcg), dissolved in 10 ml of peanut oil, on the day of admission. The placebo group just received 10 ml of peanut oil, without the added vitamin D.

The average age of the participants was 53 years and the average BMI was 32. In other words, the average participant was obese. Apart from that, chronic health conditions were common among the participants. 53% had hypertension, and 35% had diabetes.

This is a good thing, because the sicker the patients are before getting covid, the greater the probability that the study will show a meaningful impact on things like mortality and ICU-admission (assuming the treatment actually works). If all the patients are healthy to begin with, as in the previous study, then mostly likely no-one is going to die, and no-one is going to end up in the ICU, regardless of what you do.

The mean time between symptom onset and receiving the bolus of vitamin D was 10 days. This is quite late in the disease course. In general, the people who get really sick from covid start to get worse at around day 7 after the onset of symptoms, and are at their worst around day 10-14, after which they usually start to get better. So this actually creates a problem. If the study fails to show benefit, it could simply be due to the fact that the vitamin D was given too late to have an effect.

This is especially true considering that the participants were given regular vitamin D, which needs to be activated in the body, first to 25-hydroxyvitamin D, and then further to 1,25-hydroxyvitamin D, before it can start exerting its effects. Remember that in the Spanish study that showed a huge reduction in ICU-admissions, the patients weren’t getting regular vitamin D, they were getting 25-hydroxyvitamin D, so the first step had already been carried out, which would have meant that it started exerting its effects on the body more quickly.

On average, both groups had serum levels of 25-hydroxyvitamin D of 21 ng/ml, which is pretty low, and in line with the large amount of observational evidence showing that people with low vitamin D levels are more likely to become seriously ill if they get covid.

So, what were the results?

Average length of stay in the hospital was seven days in both groups. 7,0% of the participants in the vitamin D group died, compared with 5,1% in the placebo group. 15,8% in the vitamin D group ended up receiving intensive care, compared with 21,2% in the placebo group. None of the differences was even close to being statistically significant.

That’s disappointing. Giving a high dose bolus of vitamin D at ten days after symptom onset had no effect on the disease course. This is the biggest, highest quality study so far, and on the face of it, this would suggest that vitamin D is ineffective as a treatment for covid-19.

However, as mentioned, there are two reasons to think that there still might be a place for vitamin D as a treatment for covid. The first is that it was given late in the course of the disease, and the second is that the patients were given regular vitamin D, not 25-hydroxyvitamin D. So, it’s still possible that high dose vitamin D given early and/or in the form of 25-hydroxyvitamin D is an effective treatment. That is certainly what the Spanish study suggests. Hopefully more studies will be coming out in the near future that can answer this question.

Luckily there is now mounting evidence that ivermectin is a highly effective treatment for covid, so we don’t have to get too despondent if vitamin D doesn’t pan out. And even if vitamin D does turn out to be ineffective as a treatment for covid, that doesn’t mean it’s ineffective as a prophylactic.

As I’ve written about previously, there is strong evidence that a daily vitamin D supplement decreases the relative frequency of viral respiratory infections by almost 50% in people who are vitamin D deficient. And, as mentioned already, there is a lot of observational evidence showing that people who are vitamin D deficient do worse when they get covid. So I think it’s a good idea to take a daily vitamin D supplement. 4,000 IU (100 mcg) is probably a sufficient daily dose to get the full benefit, and is within the bounds of what the FDA considers a completely safe dose to take on a daily basis.

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58 thoughts on “Update on vitamin D for covid”

  1. Hi, I have read that eating vitamin D as a supplement can acctually be dangerus? That it can cause other problems?! Is that not true??

  2. I don’t think vit D has not so much effect anymore if you give it to a sick person. It helps a little. I think vit D has his effect before you went ill.
    There are studies who said that 50 a 60% of the older people and people with a darker skin living in the north has to less vit D (and C).
    If you give summer and winter enough vit D and C to the people than it works preventing.
    And then you see again that a good life style, enough vegetables and fruit, (less/no sugar, alcohol, smoking, junk food). Going a lot outside for walking/moving, even sitting outside, having social contacts, keep your mind busy, take supplements if needed, have also fresh air in your house!
    That prevents you from illness.

  3. In the Spanish study, doesn’t the huge effect mitigate the small number in the trial? Isn’t the need for ICU treatment based on objective measurement unlikely to be influenced by other considerations?

    1. Well, ICU admission is a decision made by a doctor. I wouldn’t put it past the doctors doing the study to preferentially admit people in the control group to ICU in order to get better results. You might think that makes me extremely cynical, but those kinds of things have happened many times in the past.

      What is shocking is that the Spanish study still hasn’t been followed up by a large double-blind trial doing the exact same intervention. Considering the apparent size of the benefit, you would think that every large research hospital in the world would have wanted to do that study.

      1. IF I had a financial – Or “Reputational” – interest in selling ‘vaccines’ and/or Very Expensive (late stage) ‘Treatment’, I’d be most reluctant to fund or encourage….. a study on a cheap, easy, self-dosed, non-patentable and Safe…supplement.
        Cui bono

  4. Good work and life saving too. We take plenty of D3 plus C zinc and Quercetin. Ivermectin in the cupboard. What we desperately need is your thoughts and actions on Ivermectin. It is a scandal that here in the UK journalists are not talking about it. The ethical failure of our profession is shaming.

    1. Hi David,

      Are you able to reveal where you sourced your Ivermectin? I am in the UK too.uk

  5. I have read that single high dose bolus dose, ie once a month is ineffective. To have a meaningful effect it has to be a regular daily dosage.

    1. This article is the usual vegan propaganda rubbish. The author clearly ignores the fact that people living near the equator have consumed meat obtained by hunting and fish as part of their diet for millenia so this nonsense about “rich” meaty western diets being the cause of disease is simply not logical. It is eating highly processed food full of calories but low in nutrients that is most likely responsible for diseases of civilisation. He also ignores the role of oily fish in the diets of people who live at latitudes where it is just not possible to make vit D in the winter. He also ignores the fact that a 70 year old skin makes only one third that made by a 20 year old skin so grandma exposing her arls and faces for 5 mins twice or 3 times a week isn’t going to cut it.

  6. There is also made studies of high dose intravenous vitamin C for Covid-19, can you please analyse them also? You can find information about them on http://www.doctoryourself.com/
    What do you think about treating covid patients with an intravenous mix of vitamins and minerals? We know today that the immunsystem needs these micronutriens in right propotions to eachother to properly work…

  7. Reluctantly, I’m forced to consider there is some interference going on, to keep up a certain level of ‘Fear’.
    Case in point would be Western Australia. We’ve – Sunday afternoon – gone under LOCKDOWN, due to a virus escaping from a quarantine hotel and infecting a staff-member… Masks are mandated IF we leave our front door. But the interesting co-incidence is… long, detailed report on radio news, of Brazil / Manaus being over-run by a new killer VARIANT.
    Timing? – our State Government is up for elections in 6 weeks time…

    Ivermectin ? – go here for a couple of US dollars / a Pound or so.
    https://www.rxindia.com/medicines/medicines-by-therapeutic-class/covid-19/ziverdo-kit/ They require a Prescription.

  8. so where does one purchase 25-hydroxyvitamin D? also, it is my understanding that magnesium has a synergistic effect when taken with and with respect to Vitamin D. Can you comment on both of these points, please ?

  9. hi thx for the link – anyone got some good tips on getting a legitimate online prescription for this (if such sharing is allowed by Sebastian)- also the next hurrdle I guess would be getting the package into US/Europe. it could be handy to have in the cabinet if needed.

  10. Martin, I suspect it might stay in your cupboard unused. There is a very small chance of any one of most of us suffering anything from the wuflu virus. Many people however are suffering adverse effects of the untested vaccines.

    Vitamin D, everybody (except experts) knows vitamin D is good to have. It is the anointed ones that know better and their grand plan is hands face space and a liberal dose of vaccines. Any one will do, mix and match if you can’t get your preferred choice.

    https://youtu.be/GDlF-z_x7vc This illustrates the problem.

  11. I find it disconserting that these studies run by doctors show how lacking some of them are in doing properly run studies.

  12. Speaking on a personal anecdote of one, the dose of the vitamin D should be given daily. Once over the worst of the effects I sat on the balcony of my apt in Spain, unable to leave unless shopping. The weather came good and it was great to get out into some fresh air and later I felt the event had, obviously, lifted my mood but I was convinced there was more to it as I had a surge of energy that evening. The next day was cloudy and I was indoors yet the day after was very sunny and I stripped off in 25C and sunbathed – definitely a good effect that night and so I continued it.
    The effect was real for me but it is not on the virus but on the metabolism? Vit D affects Calcium transport and other drugs such as anti-malarials have a similar effect I think?? The benefit is not directly on the virus as I would expect the effect to be stepwise improvement and not temporary (about a day) as in my case. However if the patient was deficient in Vit D the effect of a one shot dose may be to get them sufficiently up to normal levels as to be beneficial in helping the other body functions to recover?

  13. I will send the latest study on the effectiveness of hydroxychloroquine when given at an early stage. In North America this drug has been ignored for purely political reasons.

  14. Vit D as treatment needs to be the form that is immediately available for immune support – such as the activation of T-cells and many other known functional dependencies on available Vit D.
    Supplementation can take up to 14 days to be synthesised by two stages to the relatively short lived form the body utilises.
    So supplementation is the maintaining of condition for full immune function and not a ‘treatment’ except as injected in the active form.
    I felt this worth highlighting.
    Your endpoint of just take 4000IU daily – or a larger dose periodically in similar ratio would cover the essential need unless one was severely deficient and then a short larger dose would be in order.
    All of course for when sunlight is unavailable.
    I’ve seen all kinds of recommendations from those who have studied it that range from 3000IU to 10,000 IU as a daily adult dose.
    Higher dose may be worth adding Vit K2 mk7 or mk4. Among many other function K2 operates as a ‘parking attendant ‘for calcium – even to move it from where it is not needed to where it is. Calcified arteries are not helpful!

  15. I infer that if immune functions such as inflammation use Vit D then they can also use it up or deplete, and that a chronic state of anxiety and strain is also an inflammation in the body.

    The idea of preventing respiratory infection may that of preventing a backlog of toxic condition (house cleaning), by running a clear as you go efficiency, but if there is a need to clear out, then suppressing the symptoms may damn up to generate a more sever crisis via other means and it is this sort of thinking that is absent in the main from viewing disease in compartments.
    So death and sever clinical illness by all means should be part of a true accounting.

    Anyone who presents a set of accounts will know there are ways of structuring and defining the data so as to make things seem to disappear.
    Doctoring the data is where the effects dictate the causes – and the narrative is invested in as if solid ground.

  16. Here is Alaska, we have some of the best numbers for the virus–compared to many other ‘developed’ areas. Most of us always (and have been for years) are taking vit D-3 and zinc and other supplements. I suppose it helps that at 1 person per square mile population density (we invented ‘social distancing’…), the relatively few cases we’ve had are weighted to the areas of highest population density. Like as is shown in large urban centers, areas where people are layered on top of one another–of course the virus is most prevalent.

    Beyond that, one has to wonder why areas in this world, with the poorest medical care, high densities, poor diet and living conditions–the virus is almost non-existent. Why?

  17. Sebastian, as you explained earlier, vitamin D should not be taken in one big bolus but regularly to be efficient, and the best practice would be to adjust its levels for prevention already. At day 10, on the expected peak of symptoms, it wouldn’t make much sense to begin with a vitamin D medication. I expect that to be known by other doctors as well. So why should they set up their study so that it is very likely to show suboptimal results?
    I know this is a daring hypothesis, but might it be that these people want to divert the attention and crush the claim that vitamin D is just as good a prevention as the vaccine?

    1. The difference between a Conspiracy Theory and… Fact, is now heading to around 8 months.
      Yes, your suspicions regarding ‘rigging’ a RCT are not novel. I understand a similar apporach was used in a Trial on Dr Marik’s SEPSIS protocol.
      By various means, his “5 hour” window-before-futility, was engineered to around double that in the Trial.
      Naturally, the results were….. ‘Disappointing’.

  18. One can easily imagine that a test to try and prove the effectiveness of Vit D as a medicine could easily be compromised. For the time being could we just have the data showing the Vit D levels of those who have died from COVID? I do not believe there is not a correlation.

  19. Thank you Dr. Sebastian. I tell my patients that vitamin D3 is not a “treatment” for anything other than “vitamin d deficiency” which (in my office) I define as being below 40ng/ml. My favorite authority on vitamin D (happens to be my former classmate from many years ago) is Alex Vasquez. He is a nutrition genius. He now lives in Spain and blogs and writes textbooks, he does not practice medicine any more. If you are not familiar with him, check out his work. https://www.facebook.com/InflammationMastery Finally, on a personal note, my 89 year old mother recently contracted covid-19. She is in a care home in NY (wherein 17 out of 127 residents died in a 6 week period last spring, a another handful died this winter with sars cov-2 virus). Anyhow, she contracted the virus about 4 weeks ago and had about 2 days of mild flu-like symptoms and then was back up out of bed and is fine now and testing negative again and feeling “normal”. She has been supplementing long term with approximately 5500 iu per day which is the highest daily/longstanding dose of anyone in her care home (according to the pharmacy technician). He blood levels are currently in the 40ng range. 🙂

  20. Might vitamin D, Dr. Rushworth, like salt, when taken in amounts in excess of what a body requires for correcting a deficiency, simply excrete in the urine?

    1. Vitamin D is fat soluble, so it isn’t excreted through the kidneys. It’s not like B-vitamins, that you can take monstrous quantities of, because any excess just gets excreted in urine. Since it’s fat soluble, large amounts can be stored in the body, which is lucky for those of us who live in the far north and barely get any sun for much of the year. It is primarily excreted by the liver.

  21. The idea that Vit D could be helpful reached me by March last year and I decided it wouldn’t hurt to get some in. But when I asked for it at the local pharmacist they rolled their eyes at me and asked why I wanted it. Then they told me it can be dangerous to supplement with Vit D if you already have enough in your system, so they strongly recommended people get their levels tested first. So I am surprised to hear you have no concerns about this, Dr Rushworth, and see that here is yet another matter one which there is a wide spectrum of views, leaving your ordinary mortal like me rather confused!

  22. Simon, we know vitamin D is essential. We know lack of vitamin D causes problems. We do not need another test to demonstrate it. This clamouring for tests about everything just wastes a lot of time and money.

    And while I’m typing, https://youtu.be/hRP1D1j1jgs people will find an explanation for “long covid” here. It is nothing different than from any other viral infection. Some people get it, others don’t.

  23. Helen, I’ve been having 10,000IU a day for the past year. As far as I can tell, I’m not dead yet, some might disagree, or hope I am wrong. I suspect the views that you should have a small amount comes from the anointed ones. If you take the wider information, there are many people having 5,000 to 10,000IU a day and they have to buy some more the following year. That appeals to me as evidence. I suppose it could be dangerous, as many people smoked for decades and survived, many didn’t. I’ve just received an order for 5 pots of 10,000IU soft gels, I didn’t get any hassle as I used ebay. Same brand as last year.

  24. Dr. Sebastian, what is the chance that your review of studies with vitamin D and ivermectin will impact the prevention and early treatment of COVID-19 patients in Sweden? Right now Sweden is above Brazil in deaths per million. We don’t have the hospital treatment quality you have but we have more doctors (about 5%) doing early treatment and some people are self medicating themselves with ivermectin.

  25. Hello Doctor, in the Brazilian report it states that

    “They also had to have symptoms that were severe enough to require hospitalization, or risk factors for more serious disease, such as diabetes, heart disease, cancer, or obesity. So far so good – they were looking primarily at people who were quite sick, or at least at increased risk of becoming quite sick”. It then goes on to say that they excluded participants in that group who already took a vitamin D supplement.

    Do you know if they (or indeed anyone) has monitored those already taking supplements? and what effect if any the supplements had as that would also indicate (sure not double blinded) the effectiveness of vitamin D and it would also be a better reflection on the level of ‘immunity’ those that are supplementing already have.

    I guess what I’m getting at is if the studies say “taking vitamin D is effective at lessening the symptoms of covid”. Then those people that are already supplementing will think they are less prone to catch the disease, whereas all the studies seem to be giving the patients massive quantities of the drug in amounts that most people wouldn’t consider (and aren’t) taking at present so could be giving people false hope.

  26. The published evidence and the clinical practice in some places I follow in Brazil, not to mention the use in India, Turkey, Senegal, etc. points to an effective agent provided that it is taken really early, within the1st to the 4th day after the initial symptoms together with zinc and azithromycin. All effective agents like ivermectin, and nitazoxanide should be accompanied by zinc, an ionophore (hydoxichloroquine or quercetin), and vitamin C and D. For references visit https://hcqmeta.com 196 studies, at least 19 RTCs and good results for early treatments. One advantage, using the low safe dosage, is that HCQ is safe for children, pregnant women and breast-feeding women.

  27. Hi Sebastian,

    thanks for the article.

    What stops the hospital you are working for to do such a trial? This is not a cynical question. I have no clue how the regulations for such studies are. So serious question from my side.



    1. Well, the first problem is that we don’t even have ivermectin in tablet form in Stockholm county. Apart from that, I think the doctors who decide on what research gets done at my hospital mainly follow the big medical journals. Since none of them are talking about vitamin D or ivermectin, I don’t think it’s even occurred to them to research these things. Most researchers are not very innovative, they go with the flow and do what everyone else is doing.

  28. Time to look again then. Maybe start here with Risch’s op-ed (Risch is an MD PhD Professor of Epidemiology at Yale), then read his underlying paper, then read the papers underlying that paper. I did, and I’m just a citizen. Scores of studies, but about six of the best will suffice. I think you’re significantly behind on the HCQ research, doc. I do appreciate your other work here.


  29. I just found this incredibly useful tool from Our World in Data:

    It is a manipulable graph that shows deaths per million on a daily rather than a cumulative basis:

    It enables one to effortlessly compare how any two or three or ten countries are faring on an ongoing basis. Most graphs are cumulative and so they would miss the fact that Sweden did poorly at the beginning of the pandemic, but have done much better since August. (Sweden appears to be doing very well this past month, but the final numbers are obviously not yet in.) For example, the USA is doing more or less the same as most European countries. This is truly remarkable when one considers that they have by far the highest rates of obesity and diabetes in the world. This is definitely not the impression one gets when one watches CNN or NBC!

  30. My D-vitamins hsa the dosage in a small warped u and g (62,2 ug and 10 ug ) and IE (2500 IE). Do these correspond to the two units in the article?

  31. Correct and important information. HCQ used as Dr. Risch explains is immensely beneficial. Data is abundant about the early use of HCQ. And, as Dr. Sebastian noticed, other very effective drugs joined HCQ like ivermectin. In Brazil, a very successful intervention in the city of Porto Feliz combine HCQ and ivermectin. And data appears also for nitazoxanide and favipiravir. The myth that acute viral infections cannot be treated will, hopefully, be chattered by the COVID-19 crisis..

  32. I had an experience with Vitamin D. My lab work showed I was at 19 on my vitamin D level. I took daily Vitamin D for 3 years and could only get to level 26. My Dr. suggested I take 50,000 units every Sunday; suspecting that my body would respond better. It did. I was at level 60 after 6 months. Now I take 5000 units daily to maintain.

  33. I also forgot to mention, I am an RN (60 years old) and work with Covid-19 patients. We are tested at work twice a week. I have never been Covid-19 positive…I am taking Vitamin D, Quercetin, Zinc, Vitamin C…to combat the virus. So far, so good

  34. Hi Sebastian and readers!

    I just came across this excerpt regarding two plausible modes of Covid-19 transmission which aren’t what we think when it comes to saliva or mucus. I’d like to share it, as it to me (not a medical professional) it does seem to make a lot of sense and comes with all the sources. But perhaps someone more knowlegable in pathogen transmission and virology could take a look at it and let me know what you think! If this theory is truthful then we have been avoding transmission through completely wrong methods, so it’s a very important theory to regard.


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