vitamin d hammer for the flu

The (Improved) Vitamin D Hammer: Beating the Flu in 72 Hours

​Recently, when my ​father came down with a bad cold, we made use of the “Vitamin D Hammer” along with our secret weapon ​– vitamin C. The improvement was clear.

But, what is this hammer and how can you use it to get rid of influenza-like symptoms fast?


Origins of the Hammer

I first read about this “hammer” on a forum. The name sparked my curiosity and got me to investigate further.

This led me to a research paper by Doctor Gerry Schwalfenberg. (1)

As it seems, upon reviewing some of the unpleasant side effects of the drugs commonly used to treat influenza, Dr. Schwalfenberg and a colleague proceeded to consider an alternative to them: vitamin D.

And, as it turns out, the results far exceed their expectations, hence, they dubbed vitamin D as "the hammer."

​How well did it work?

I've read, and written, a lot about the benefits of vitamin D, but I have to tell you, even I got surprised​ about they're good results.

First, just by raising the vitamin D levels of most of their patients to above 100 nmol/l – 40 ng/ml – Dr. Schwalfenberg and his colleague saw a marked decrease in the incidence of influenza.

In his own words:

​“A colleague of mine and I have introduced vitamin D at doses that have achieved greater than 100 nmol/L in most of our patients for the past number of years, and we now see very few patients in our clinics with the flu or influenzalike (sic) illness.”

– Dr. Schwalfenberg

But, what about the times when high vitamin D blood levels weren’t enough to prevent someone from getting ill?

When a patient did come down with the flu, Dr. Schwalfenberg used a straightforward high-dose protocol:

A 1-time dosage of 50,000 IU ​or 10,000 IU of vitamin D three times a day for 2 to 3 days.

What were the results?

​“The results are dramatic, with complete resolution of symptoms in 48 to 72 hours.”

– Dr. Schwalfenberg

​This is remarkable.

I’ve read countless research papers and let me tell you: learning that something caused a “complete resolution of symptoms” is rare!

So, let me ask you, the next time you beg​in feeling aches and chills, would you like to try this approach?

How to hammer down on the flu with vitamin D

Let’s break down the protocol.

If you are experiencing flu-like symptoms and want to try and hammer them down before they have a chance to develop, here’s what you’ll need to do:

​Option 1

​Hit it with a ​One-Time Dose of 50,000 IU

Upon noticing the first symptoms, make sure you take 50,000 IU of vitamin D.

Since this is a one-time dose, it isn’t expected to cause any symptoms of toxicity, far from it.

Also, to maximize your vitamin D absorption, be sure to take this first dose with a meal, like lunch or dinner.

The sooner you take your high-dose the better, so, if you are hours away from your next meal you may want to grab a snack – or two – and take your vitamin D with it.

​How safe is a one-time Dose of 50,000 IU?

Researchers who analyzed the case of a man who mistakenly took 4,000,000 international units (IU) of vitamin D for an unspecified number of days concluded that: "the estimated toxic dose of vitamin D should be greater than 100,000 IU per day for, at least, one month.” (2)

If a regular healthy person can withstand a dosage of 100,000 IU of vitamin D, per day, for a full month, it stands to reason that the side-effects of a one-time dose of 50,000 IU would be negligible.

Still, given the potential ​effects of vitamin D ​over your calcium metabolism, you’d still be advised to increase your water intake during the “hammer protocol.” Better yet, be sure to take​ at least your vitamin B2, magnesium and vitamin K2 too.

After all, these three co-factors are essential when your goal is to increase the safety profile of vitamin D.

​Option 2

Take 10,000 IU of vitamin three times per day for The following 2 to 3 days

This might be different than what you’re used ​reading about.

After all, most high-dose vitamin D protocols call for a single dose of vitamin D once a day or even once a week.

However, keep in mind that the goal of the “hammer protocol” is not the same as with the Coimbra protocol.

With the Coimbra protocol, you take a high-dose of vitamin D tailored to your body’s resistance to vitamin D.

And, as long as you keep taking that daily dose, you’re making sure your immune system is kept in check.

With the hammer, on the other hand, your goal is to provide the biggest blow you can to the invading microbes.

With this goal in mind, it seems that the idea behind the divided doses is that they’ll ​stimulate your immune system several times throughout the day.

​Why would this work so well?

Let’s see.

Why would Vitamin D help with the flu?

In February 2017, the University of Harvard published an article entitled "Study confirms vitamin D protects against colds and flu."

This study consisted of an analysis of more than 11,000 participants from 25 other studies. (3)

Why would vitamin D help you fight a respiratory infection?

When your body is invaded by a virus or a bacterium, your white soldiers work hard at producing substances specially designed to destroy those invaders.

Vitamin D stimulates your immune system to produce these very antimicrobial proteins.

That’s why Dr. Schwalfenberg saw such a marked decreased in the incidence of influenza-like symptoms in his patients.

The lesson couldn't be clearer: Get your vitamin D levels up and your chances of getting sick go down. This is true even if you are a healthy person.

For example, it has been reported that even a healthy person is twice as likely to get influenza when their vitamin D levels are low. (4)

As you can see, everyone stands to gain from striving to keep their vitamin D levels in check and, especially so, during the flu season.

​Therefore, if you do get sick, it stands to reason a high dose of vitamin D will jumpstart your immune system in a safe way.

Then, by frequently supplying just enough vitamin D throughout the next 2 to 3 days, you’ll keep providing a gentle stimulus over your immune system.

The idea of using vitamin D to fight of the flu isn’t exclusive to Dr. Schwalfenberg, though.

In my book, you can learn how a renowned Portuguese professor, Dr. Manuel Pinto Coelho, recommends increasing the dose of vitamin D to 2,000 IU per kilogram (2,000 IU per 2.20 pounds) for 3 days at summer’s end to avoid the winter flu.

If you happen to weigh 150 pounds (68 kilograms), this would mean taking 136,000 IU of vitamin D per day, for 3 days.

Of course, any dose above 100,000 IU would qualify as a very high-dose and shouldn’t be taken lightheartedly – in fact, I advise you against taking such dose without proper medical supervision and the accompanying lab tests – but this serves to illustrate the point: high-dose Vitamin D is highly regarded by some Doctors as a tool to help your body fight off an invading microorganism.

Similarly, Dr. Coimbra patients have reported on how they’ve been advised to double their vitamin D dosage during a flair-up.

This means that, if you ​were taking 40,000 IU of vitamin D every day to keep your autoimmune disorder under control, you’d take 80,000 IU for a couple of days to better deal with an impending flair-up.

With this concept of “doubling down on vitamin D for a couple of days in order to deal with a health issue", let’s take another look at the flu protocol again.

How to improve the hammer, making it better, faster and safer

How can we improve on Dr. Schwalfenberg protocol?

First, we can make it stronger.


By increasing the vitamin D dose.

But, by how much?

That’ll depend.

As we’ve seen earlier, if you’ve seldom supplemented with vitamin D, research shows that 100,000 IU per day can be safe for a period of up to 1 month – provided that (1) you are an adult with healthy kidneys (2) and bones, and (3) you are sure you don’t suffer from either hypercalcemia (too much calcium in your blood) or hypercalciuria (too much calcium in your urine).

Therefore, if you have come down with a cold or the flu, we can make an educated guess that a one-time dose up to 100,000 IU would be a safe, and extremely strong, way of fighting off any invading microorganisms before they’d take hold of your body.

​As for option 2, you could ​use the same principle of “doubling ​up” and take 20,000 IU 3 times per day, instead of just 10,000 IU.

That would amount to ​60,000 IU per day.

You’d then do this for 2 or 3 days – depending on whether you felt significantly better on the third day or not.

Then, you’d stop supplementing with vitamin D, giving your body enough time to recover from any possible ​toxicity.

On the other hand, if you suffer from an autoimmune disorder and are already undergoing a high-dose vitamin D protocol, I can't really ​advise you to increase your vitamin D intake as that could prove dangerous.

Please refer to the accompanying box for more information on why this ​would be the case.

​Why you shouldn’t raise your vitamin D intake to deal with the flu when you already regularly take high doses of vitamin D

When you’ve been taking high doses of vitamin D for several months, your calcium blood levels will have the tendency to be higher than normal.

This is a given and the main danger associated with a high-dose protocol.

This means that a sudden increase in your vitamin D intake could potentially cause a calcium spike in your blood – a condition known as hypercalcemia.

Of course, you could choose to “double your dose,” as if you were dealing with a flair-up from your autoimmune condition.

But I would advise against that.

This is just my personal opinion, but I do think you should save that double dosing for when it’s really needed.

No point in risking overwhelming your kidneys just to make the flu disappear faster.

Besides, if you’ve been on a high-dose protocol for many months, I’m sure that your Doctor has already found the highest dose that your body can safely tolerate.

This means that your circulating vitamin D levels are already at their peak in what concerns their ability to stimulate your immune system to function properly.

It’s as if you already lived in a permanent state of “hammering down on the flu,” so to speak.

This means you should already expect a quick recovery; no need to risk overwhelming your system with more vitamin D.

I hope this makes sense to you.

If not, let me know in the comments.

The next step to improve the hammer is to make it safer.

As referred to above, the essential vitamin D co-factors include vitamin B2, vitamin K2, and magnesium.

Make sure to include them in your daily regimen while you are taking vitamin D.

Also, be sure to drink a lot of liquids – think 2.5 liters (85 fluid ounces), including soups and juices – and to avoid calcium-rich foods.

  • ​If you need help in determining which foods could be considered to be calcium-rich, be sure to check this handy list of the 114 foods richest in calcium – some of which may surprise you, like tofu or chocolate.
  • ​Also, if you’d like to learn more about the 13 rules of the Coimbra protocol diet, feel free to check the linked article.

Safety is very important, and the ultimate safety measure is ​being aware of your blood and calcium urine levels.

However, since these lab results may take several days to become ready, it’s not feasible to measure them before starting the anti-flu protocol.

Instead, measure your levels after you’ve overcome the flu and stopped the (improved) hammer protocol.

Even though a single dose of 100,000 IU of vitamin D (followed by 2 to 3 days of 60,000 IU taken in divided doses) isn’t expected to harm you in any way when you are healthy, to begin with – to the contrary (!)​ – by measuring your calcium levels afterwards, you’ll be sure that you aren’t experiencing any form of vitamin D toxicity.

A secret weapon to beat the flu

From my own personal experience, besides vitamin D, there’s only one other supplement that I’ve consistently used against influenza-like symptoms with great success:

Liposomal vitamin C.

The smaller box contains 30 individual packets and usually lasts me a long time since I only take these the moment when the symptoms begin.

It’s not cheap, but it’s worth every penny.

​What I do is I’ll try to always have at least one of these boxes available at home. When I travel, I also make sure to take them with me.

At the first sign of a cold, or flu, I’ll immediately take one or two of these vitamin C packets with water – it depends on how many I have available.

For example, when my ​father came down with ​that bad cold, I gave him 2 packets of liposomal vitamin C per day in addition to the vitamin D.

Given the potential for the flu to turn into pneumonia, I’d rather not take any chances.

I found ​these tiny packets to be really effective, so do my wife and my ​father.

You can usually feel the effect within hours as long as you take them right after the onset of the symptoms.

Even if you do get sick, you are not expected to be sick for as long, or as severely. (5, 6) Although not all researchers agree, that has certainly been my personal experience.

And that’s my secret weapon, in addition to vitamin D.

​However, you should exercise caution when adding vitamin C to high-doses of vitamin D. Once again, please refer to the accompanying box for more information on why this ​would be the case.

​If you are taking high doses of vitamin D you must be careful about any extra vitamin C supplementation


​Because Vitamin C ​is known to break down into oxalates.

This can be a problem because of how oxalates can combine with the minerals in your kidneys to form crystals, or stones.

Now, as you know, if you are following a high-dose Vitamin D protocol, your kidneys will tend to have a higher mineral concentration than normal.

D​o you see where this is going?

​Of course, if you are limiting your vitamin C intake to just the 2 or 3 days required to jolt your immune system into fighting off the invading microorganisms, you'll most likely be fine.

​Therefore, if ​you are not ​following a high-dose vitamin D protocol, I'd even ​advise you to take one of these packets every other a day, throughout the year, as a ​preemptive measure against respiratory tract infections.

​On the other hand, if you do take ​high doses of vitamin D regularly, add t​he secret vitamin C weapon to your anti-flu arsenal ​only for the first 2 or 3 days of your hammer protocol.

If you are known to be at risk for kidney stones, skip the vitamin C entirely.


The Vitamin D Hammer

  • ​At the first sign of a cold or the flu take 50,000 IU of vitamin D right away.
  • ​Alternatively, in the following 3 days take 20,000 IU of vitamin D in 3 daily divided doses of 10,000 IU.

​The Improved Hammer + The Secret Weapon

  • ​At the first sign of a cold or the flu take a one-time dose of 100,000 IU of vitamin D plus 2 packets of liposomal vitamin C.
  • ​For the following 3 days take 60,000 IU of vitamin D in 3 daily divided doses of 20,000 IU each and keep taking a packet of liposomal vitamin C two times per day.
  • ​If (1) your budget allows, and (2) you are not taking high-doses fo vitamin D regularly (3) nor at risk of developing kidney stones, make sure to keep taking a packet of liposomal vitamin C ​every other day as a preemptive measure against influenza-like symptoms.
Tiago Henriques

With more than 10 years of experience as a Public Speaker, Tiago Henriques has done hundreds of public talks. He was born in 1987, in Portugal, and is the Author of 3 books — and counting — and the creator and editor of the Portuguese Science Project, "Ciência Desenhada," where complicated science is explained in a simple way, using whiteboard animation techniques. Tiago developed his own practical and down-to-earth teaching method inspired by his experiences with the Portuguese Deaf Community and their use of highly visual, descriptive and easy-to-understand language.

  • Cara says:

    While I feel that your protocol is probably very effective, I just want to point out that there is an error in this information. In the original article discussing “the hammer,” the protocol used was one 50,000IU dose OR 10,000IU 2-3 times daily for three days. Not both together.

    • Hi Cara, thanks for your comment.

      You are correct. I edited the article accordingly. I left the combination protocol in the end as a way to improve the hammer as that’s the one I’ve successfully been using.

      Thanks for pointing out the mistake.

      Tiago Henriques

      • Alise says:

        Hi Tiago,

        I would like to know if you do online consultations? Please contact me: Alise:

        • Hi Alise, first of all I’m sorry for the very late reply. Unfortunately I don’t do any kind of consultations as I’m not a medical professional. I appreciate your positive comments but I’m just trying to convey what I’ve learned from reading the work of others far more intelligent and capable than myself such as Dr. Coimbra. I hope my book helps you to steer your health into a good direction.

  • Deb says:

    I have a question about taking another vitamin with high doses of D3, which I’m currently taking (75,000 IU since July 2019). Would taking boron be a problem or any risk with high doses of D3? I’ve read research that showed boron is good for bones and healing, so I would like to take it for those reasons.

  • Janice says:

    What would be the ratio of vitamin B2, magnesium and vitamin K to the vitamin D?

    • Hi Janice,

      The usual recommendation is to take 100 micrograms of vitamin K2 for every 10,000 IU of vitamin D3. For magnesium and vitamin B2 please check these two excerpts from my book:

      Dose recommended in the protocol: 125 to 250 milligrams of magnesium chloride or magnesium glycinate, 4 times per day.
      Best taken: With food as it increases the absorption of magnesium.
      Daily total: Between 500 and 1,000 milligrams.

      Vitamin B2
      Recommended dose in the protocol: Between 50 to 100 milligrams, 4 times a day.
      Best taken: With some food to reduce any gastric discomfort.
      Daily total: Between 200 and 400 milligrams.

  • Claudia Acevedo says:

    What’s a safe dosage for 12-17 year olds in The Vitamin D Hammer, and The Improved Hammer + The Secret Weapon?

    • For children and young adults the question is more complex as their skeleton is developing and too much vitamin D can cause calcium to leech from the bones which may, at least in theory, disturb that process. So I’d check with the child’s primary care physician first. However, for reference, in studies on autism and vitamin D, 106 children with autism who had blood levels of vitamin D below 30 ng/mL received a daily dose of vitamin D corresponding to 300 IU for each kilogram of body mass (300 IU per 2.20 pounds), but without ever exceeding daily 5,000 IU. 83 children completed 3 months of treatment. Afterwards, 67 of the 83 children who received vitamin D showed improvement in their autistic symptoms.

      However, based on the health status of a particular child and their vitamin D blood levels, a Doctor may recommend an higher or lower dosage.

  • Morrie says:

    Which liposomal C do you use>

  • diana says:

    Iam on 10000 UI from a month. May i take 1000 mg vit C?

    • Hi Diana, for an healthy individual, such doses wouldn’t be problematic. In the context of vitamin D supplementation, 10,000 IU isn’t even considered a dangerous dose as it’s the same amount of vitamin D that your skin would produce after a few minutes under the midday Sun.

      But, as with everything, make sure to double check with a Doctor that is well aware of your clinical history and current health status. Also, be sure to take your vitamin K2 and magnesium.

      If, however, you are known to have kidney issues or hipercalciuria (too much calcium flowing trough your urinary system)), the vitamin C could actually increase your chances of developing kidney stones.

  • gabriel says:


    my levels are currently around 100 nmol/L, I take 4000 IU a day.
    Let’s say I do get a bad case of the flu, do you think I should try the Hammer Protocol? I also take K2 about 180 micro grams a day.

    Thank you fo finding the time to answer.

    Kind regards

    • Hi Gabriel,

      I can’t give specific health recommendations apart from highlighting that magnesium is also important when taking vitamin D. I can say, however, that I up my dosage anytime I get flu-like symptoms. Within hours of symptoms appearing I’ll take liposomal vitamin C and the higher dose of vitamin D. Symptoms will get better within the day. However, since the symptoms never develop further, I still wonder “was I really about to get a cold, or the flu, or was this simply a passing allergy that would have resolved on its own anyway?” Hence the importance of scientific studies to fully establish the therapeutic value of any protocol. However, on the absence of such a possibility, and speaking personally, I choose not to risk it, and I through the hammer at the flu-like symptoms right away.

  • Nancy says:

    My son has Down syndrome he is 30. Has coinfection of Lyme
    Pandas syndrome. He also has high uric acid
    He is low vitamin d. Can I give him vit d and c

    • HI Nancy, thanks for reaching out. I’m so sorry that your son is going through all that. Unfortunately, I can’t give you specific health recommendations as your situation is outside of my little bubble of knowledge.

      However, everyone needs vitamin D, specially so if one’s deficient. But if a person is very deficient and suddenly supplements with a high dose this can exacerbate other underlaying deficiencies. Vitamin D supplementation, for example, can exacerbate an underlaying magnesium deficiency because vitamin D will tell your body to start processes that require magnesium. That’s why magnesium is one of the co-supplements.

      The high uric acid is also worrisome as healthy kidneys are key to vitamin C and vitamin D safe supplementation. Vitamin C is know to, in some circumstances, promote oxalate formation. Vitamin D, on its hand, is known for its potential to raise calcium. This is usually not a problem as healthy kidneys will filter out any excess of these substances assuming you’re drinking enough water. However, high calcium + high oxalate concentrations on your blood can promote the formation of kidney stones. If you want to learn more about vitamin C from someone who really knows what she’s talking about, I recommend this presentation by Dr. Rhonda Patrick:

      If Down syndrome were the only issue, I’d urge you to look into something called “The Nemechek Protocol” by Dr. Patrick Nemechek. On at least one of his videos he speaks about reversing the cognitive aspect of Down syndrome. The protocol is pretty straightforward, not nearly as complex as the Coimbra Protocol. Certainly not requiring all the blood and urine testing. His book on autism also contains a description of the protocol. I’d advise on not doing the protocol on your own though, given the other health issues your son has.

      Hope this helps, feel free to email me if you hit a road block on your research.

  • Jennifer says:

    Is 5,000IU’s considered a high daily dose of Vit D?

    • Hi Jennifer, I guess it would depend on who’s taking that dose. But, for an adult, 10,000 IU is what you usually find on vitamin D supplement bottles as, if my memory serves me right, it corresponds to about 15 minutes of full-body exposure to the midday Sun on a sunny day. From that perspective, 5,000 IU seems like a pretty standard dose. Usually, when someone as a autoimmune disorder (i.e. a known resistance to vitamin D) and no other concerning issues are present (he’s not a children, has no kidney issues, baseline PTH levels aren’t low, baseline calcium levels aren’t high, etc), a Coimbra protocol Doctor may start him on 40,000 IU or higher.

  • Jennifer says:

    Also, is it safe to take vit c, zinc, magnesium, vit d, bit b6 & 12 all daily? When and how should they be taken? Should I add anything? Recommendations?

    • Safe is always relative. But if you are looking to keep your bases covered (i.e. not trying to go high-dose with any of those), a good multivitamin from a reputable brand will give you all those vitamins and minerals with many of their co-factors. For example “Two-per-day” by Life Extension comes to mind. I’d only also add vitamin D separated, as theirs only contain 50ug (2000 IU). Perhaps add 5000 IU on top of that.

      Also, if you want to access the quality of a multivitamin company, a quick way to check that is by verifying which from of B12 they are offering. If it’s “cyanocobalamin” run. “Methylcobalamin” is good. Same for folic acid: You’d want a multivitamin with “methylfolate”, if it’s regular “folic acid” with no other designation, run.

      I’ve read that high-dose vitamin B6 can be problematic. So I’d caution about going above whatever is on the supplement daily recommendation.

      Also, keep in mind that many processed foods are fortified with B vitamins, so keep that in mind, as it all adds up.

      Finally, daily high-dose vitamin D + daily high-dose vitamin C is not recommended

  • Bob Harford says:

    Because I was told I have a problem with absorption, I was told to take extra vitamin d. I am using the Thorne liquid with k2 in it. I take 10,000 at night and 5,000 in the morning. I don’t take much at all in the summer because I am outside working. But I start in September. I also take 3000 of c at night and 2000 in the morning. Am I doing too much? I am 74, over 6 feet tall and about 225 pounds. Thanks.

    • Hi Bob, given your respectable age absorption issues aren’t unheard of. Also, the vitamin D requirements go up, hand in hand, with a person’s weight. However, the only way to be 100% sure is by verifying your calcium blood levels, since high calcium is the only real danger from vitamin D supplementation. As for vitamin C, an overdose will let itself known in the form of diarrhea, so if your not getting that, your body is making use of it. I’d add that mixing vitamin C with high-dose vitamin D is very discouraged due to the small chance of kidney stone formation. This is due to the increase in calcium excretion when on a high-dose vitamin D. When you got a high calcium concentration on your kidneys (from not drinking enough water to dilute its concentration) coupled with the extra oxalate production that may be promoted by vitamin C, you may be setting yourself up for some calcium oxalate stones in the future. Note that this only applies if your excreting more calcium than normal. You can evaluate this by getting a simple 24h calcium in the urine test.

  • Zadok says:

    Hey Tiago,

    What are your thoughts on medical professionals saying that because vitamin D is fat-soluble, it stays in her fat cells and can lead to toxicity? You mentioned elsewhere that vitamin D has a half-life of 2 weeks, does that mean in 2 weeks, half of the vitamin D will have left the fat cells or is that only in the blood?

    • Hi Zadok, any substance when taken in excess can lead to problems. Water soluble vitamins are excreted via the urine, so they have a much harder time accumulating in the body for long enough to cause significant problems. I.e. they are generally considered safer. However, fat-soluble substances such as vitamin D are harder to get rid off by the body when taken in undesirable amounts. In the case of vitamin D, you can’t just drink more water to get rid of it. You have to wait it out. However, I must stress that vitamin D is an extremely safe substance as long as you supplement with it under the guidance of a knowledgeable health professional.

      Half-life means the time it takes for a substance to disappear from the body or being transformed into something else. The 15 days mark is mentioned here: You can find more information on Henry Lahore’s vitamin D encyclopedia here:

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