Vitamin D Time Again-Winter Edition


Summer Sun On Bare Skin Can Generate a Lot of Vitamin D (50,000 IU/hour), but in Winter, Supplementation Becomes Important

We do not like supplements except for…

Almost the entire drugstore aisle of “supplements” have been shown to be useless for almost everyone who takes them. Furthermore, a great number of them turn out to be harmful: calcium, vitamin E, folic acid, the list is long. And to make things worse, production standards are lax compared to “real” drugs, so it is hard to be sure what you are getting. There have been fatalities due to this.

No one seems to actually believe this. They think that since the pill is on a drugstore shelf and no prescription is required, it must be harmless at worst. This is definitely not the case. It is shameful that the FDA doesn’t do more. More info on supplement testing can be found here.

All these supplements, vitamins, worts, nettles, and whatever, are drugs, real drugs, and like any other drug should only be taken if needed. If you actually have Stinging-Nettle deficiency, by all means take it, but get a blood test first. And while you are at it, check your Vitamin D level. If you are not already supplementing, it is almost a certainty that it is low, and the darker your skin, the lower it will be. A very low level is dangerous.

But why do we make an exception for Vitamin D, given the cold water we dumped on those other supplements? The reasons are simple enough. We are designed, or evolved—your choice—to be hunter-gatherers. We hunted and gathered for hundreds of thousands of years. Where we spent those millennia largely determined out skin color, and the main purpose of skin color appears to be Vitamin D regulation.

Sun, in particular the UV penetrating you skin, makes Vitamin D, and makes a lot. That hour in the midday summer sun is good for 50,000 IU. This is four months worth of those 400 IU standard pills. But the sun doesn’t shine every day, and even hunter-gatherers had to cover up in those ice age winters, so we have also evolved an ability to store Vitamin D and can store several months worth in our muscles.

Food does contain some Vitamin D and the manufacturers of this food will lose no opportunity to loudly proclaim this. However, the amounts found in food are trivial, really. After all Vitamin D is the “sunshine vitamin” for a reason.


Vitamin D not a problem here.

Now hunting and gathering are generally outdoor vocations, and this means sunshine, lots of sunshine, at least some of the year, and likely little excess clothing. So no problem generating a good supply of this marvelous drug. What could go wrong? In a word, civilization. We simply get far less sunlight than we were ever designed to get. Furthermore, any one from a tropical region that now lives in a temperate zone is getting still less. Result: endemic Vitamin D deficiency. Most people have levels are between 15 and 25 ng/ml. The official “good range” is 30-100, but realistically 40 to 100 is probably more desirable. This takes either a lot of sun-bathing (or hunting and gathering) or a rather high-sounding dose of Vitamin D. It is possible to overdose on Vitamin D, but it is not easy. Two strategies: take 20,000 IU once a week or take 5000 IU once a day. Dr. Mike has cases where 5000 IU/day didn’t work but a 20,000 UI weekly blast did. The “standard” Vitamin D pill has 400 IU. This really isn’t enough to move the meter. Again, measure and adjust. Some people will need less supplementation, and others a lot. But strive to maintain it at 40 or above. Pills with 5000 IU are widely available.

What are the other exceptions? B-12 if you are a vegan, or if the B-12 blood level is low for any reason. If visiting a mosquito infested region, B-1, triple standard dose, for the duration, may repel mosquitos. This is anecdotal, but has been very effective in certain cases, so may be worth a try. There may be some other useful supplements, but have a good medical reason, don’t just pop those pills because Aunt Gerty took one every day and lived to 101.

Vitamin D is Not Really a Vitamin D, but it is Certainly a Wonder Drug,

Vitamin D is not, strictly speaking a vitamin al all. A Vitamin is something we need, but cannot make ourselves, but we can definitely can make vitamin D: just get need some sunshine.

The list if Vitamin D benefit is long and growing. The perils of vitamin D deficiency are likewise motivating. Here are some to bear in mind.

  • Low Vitamin D is associated with dementia. In particular, Alzheimer’s
  • Vitamin D reduces the risk of heart disease
  • Vitamin D fight depression.
  • Low vitamin D is commonly found in those experiencing fibromyalgia
  • Vitamin D seems to help prevent the flu.
  • Vitamin D may aid in weight loss.
  • Vitamin D is needed for bone health (along with resistance exercise)
  • Vitamin D is needed for joint health and helps fight arthritis
  • Vitamin D lowers the risk of several cancers, including breast cancer and prostate cancer.

Do we have the order yet? Or should I keep selling?

Probably the takeaways are:

  • Most people’s levels are too low. Measure.
  • The standard pill, 400 IU/day won’t cut it.
  • Our recommendation, increase to 5000 IU/day. Back off a bit once your levels are in the 40s.

Sunscreen is making things worse

Sunscreen slows vitamin D absorption and is largely a mistake. Vitamin D—summer edition on Vitamin D, found here, mentions this.


In several European countries, children are given a 100,000 IU Vitamin D dose, in liquid form, once or twice a winter. Many adults do this as well. We could not find a study comparing efficacy to the pill-a-day approaches, but a dosage that high (though taken only once or twice a year) is certainly considered safe, even for children.

  4 comments for “Vitamin D Time Again-Winter Edition

  1. Drifter
    January 1, 2017 at 9:10 am

    Curious why no mention of the need to take Vitamin K2 and Vitamin A along with the D. Chris Masterjohn (and others) have written extensively that K2 and A are apparently cofactors in D’s role in storing calcium, and D alone can apparently put calcium where you don’t want it (in your arteries). Otherwise I agree. I feel better all around when I can get full body sun for 15 minutes or so a day when the sun is high (I believe it has to be above an angle of 50 degrees to produce D). The US naval observatory has a link for calculating this by zip code.

  2. Drifter
    January 1, 2017 at 11:13 am

    And although I really like what you’re doing here, I will register a minor quibble since it’s a pet peeve of mine, and that is the problems that come from relying on blood tests instead of symptoms when symptoms are available and trial and error can be employed at low or zero risk. My personal example is that I never tested low in DHEA but I get a definite boost from keeping my DHEA slightly above the top of range, something I never would have known if I hadn’t done some experimentation. Further, many of the studies done on DHEA that said it was of no benefit to supplement were done on young people who already had youthful levels. I could go on and on on this topic given the reports of people who were in “normal” ranges for various things such as testosterone or thyroid (normal is obviously not necessarily healthy or optimal) whose symptoms improved when they supplemented.

    • January 2, 2017 at 11:23 am

      Hi Drifter,
      Our basic premise is that properly done experiments in an individual provide better guidance than adopting generic advice. Another is that ‘normal range’ is rarely or never ‘optimal’ range. This point is better made in our book than in any individual article on the website. My biggest worry with supplements is contamination; they are often not what the label claims. So, in that light, I say: good for you! Now, one caveat: you need to check the downstream and collateral hormones to be sure you are not causing other problems. This is too big a topic for this setting. Happy New Year, Drifter. Dr. Mike

  3. Judith
    December 27, 2018 at 5:20 pm

    For a modest annual fee, one can subscribe to Consumer Labs, and independent testing site for supplements. They publish a list every month of the brands they test for contamination and other factors, a provide “Best Rated” recommendations.

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