Hi, author of the blog post here! Yes thank you for catching this awful typo, it's fixed now! I did write "4000 or 5000 IU of Vitamin D" everywhere else in the article -- main text, conclusion -- just my luck that the one place I mess up is right at the very start.

(Do not take 5000 mg, that's 200,000,000 IU. You'd have to chug dozens of bottles per day)

People don't always realize: https://www.chemistryworld.com/news/university-fined-in-caff...

More often written as 200,000 IU as 5000mg of D3 is not written as 5,000,000mcg

The author simply (and terrible mistaking) typed [mg] instead of [UI] in the first paragraph: if readed entirely, the author correct this typo in every other sentence

Why didn't the author notice? AI slop?

From NHS Scotland:

"In Scotland, we only get enough of the right kind of sunlight for our bodies to make vitamin D between April and September, mostly between 11am and 3pm."

https://www.nhsinform.scot/healthy-living/food-and-nutrition...

Personally I found that taking Vitamin D supplements made quite a bit of difference - and I spend a fair amount of time outside (~3 hours each day).

In winter, even on a sunny day, only tiny fraction of your skin is exposed to sun. 10-30 min of sun when you are wearing tshirt and shorts is much different from 10-30 min of sun when you are wearing long sleeves, gloves, and a scarf.

Check local/national advice. In many places it is officially advised to take vitamin D supplements, especially in winter or if you have a darker skin tone.

Don’t guess; just get your vitamin D levels tested. It’s $20, you can just buy it à la carte.

For some people even in sunny areas, 5000 IU might be needed to get you in-range. This is highly individual.

I would argue to do both in the winter, since sunlight has other benefits than just Vitamin D synthesis, like mitochondrial health and better circadian signaling for better sleep quality.

> it is way better to get the Vitamin D from the sun in 10-30min increments per day

spoken like someone who has never lived in the UK

Your suggestion sounds a bit detached from reality of many people.

In many countries it is physically impossible to get enough vitamin D from the sun, even if you go out naked.

Also did you ever notice that the cheap apartments in many places are facing north and do not have a balcony, and of course do not have a private garden? Now you are reduced to going to a park which in the "cheap" areas is also not a good spot to chill for 30 minutes.

Agreed, but I live in Sweden so I take vitamin D supplements every winter.

During the spring, summer, fall months I barely need it since I'm outside so much with my dog.

Next time I get sunburn I'm calling it a vitamin D overdose

This is nonsense advice for pretty much anybody that is shovelling snow right now.

.. how do you calibrate this against a cloudy sky? It's pretty dark up here at 56 degrees north, and on top of that it's been overcast for days.

It also sucks a lot when it's dark before starting work, dark after leaving work, and during the day rather cold to be exposing skin to the sun.

Oral has felt very effective for me. I take a daily supplement that has roughly 100% of the recommended daily dose of everything. I split it in half.

For D3, it is 25mcg / 1000 IU / 125%

After splitting in half it's 12.5 mcg / 500 IU / 62.5%.

I take with some fat-containing food to allow ir to absorb which is usually breakfast (yogurt, some nuts, some kind of fruit, oats), and it's a night and day difference in my mood (how easily I can control my temper if already agitated, how easily I brush off annoying stuff, takes the intensity off of my reactions and mood during conversations).

I did a blood test before starting, and if normal is between 30 - 70, I was at 10. Dr prescribed megadose of D2, followed by daily D3, but I skipped on the megadose and went straight to D3 -- makes me wonder if a megadose would build up my stores since D is fat-soluble and make it so I could miss a day and not notice.

All of the above is anecdotal from me, a self-professed cave dweller, but it's been a couple of years now, and I still notice the difference. Also, what I heard from people in Boston is that 90% of them are on a vitamin D supplement. My friend from there laughed at me when I was raving about it, saying "yeah, literally everyone here is on it".

It is easily possible to overdose on oral Vitamin D tablets and damage your body.

It's usually pretty hard to get to toxic levels though, most people that don't live in a particularly sunny climate won't get anywhere near there on 5000 IU/day.

Just test your blood levels before you start and then after 3 months or so. It's quick and cheap, and the only way to know whether the dose is right.

This was linked on here a couple of months ago: [The Big Vitamin D Mistake [2017]](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/)

> A statistical error in the estimation of the recommended dietary allowance (RDA) for vitamin D was recently discovered; in a correct analysis of the data used by the Institute of Medicine, it was found that 8895 IU/d was needed for 97.5% of individuals to achieve values ≥50 nmol/L. Another study confirmed that 6201 IU/d was needed to achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L.

> This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. Actions are urgently needed to protect the global population from vitamin D deficiency.

> ...

> Since 10 000 IU/d is needed to achieve 100 nmol/L [9], except for individuals with vitamin D hypersensitivity, and since there is no evidence of adverse effects associated with serum 25(OH)D levels <140 nmol/L, leaving a considerable margin of safety for efforts to raise the population-wide concentration to around 100 nmol/L, the doses we propose could be used to reach the level of 75 nmol/L or preferably 100 nmol/L.

It depends. I have MS and I take 10k IU. My cousin who also has MS takes 20k but gets regular blood tests for it.

According to what I read in a newspaper article, the recommended dose is much lower, at 800.

With K3! Otherwise you're fucking yourself up.

I was taking 2x2000 IU with almost no sun exposure and then did bloodwork. My level was 77.8 ng/mL. The lab's reference ranges listed 30-50 ng/mL as optimal, 50-100 as high, over 100 as potentially toxic, and over 200 as toxic.

5000 IU is very high, might be beneficial during the winter for folks with very fair skin. but most probably shouldn't take that much every day

No, it's to make it easier to dose different kind of biologically active substances. They can have significantly different "recommended weight to eat of this per day", IUs make that sort-of comparable and easier to remember.

https://en.wikipedia.org/wiki/International_unit

Wow, so what value is there in LLM slop exctracted from already dubious self-medication advice?

Being at the beach (in summer) for a half an hour will produce 10,000 and 25,000 IU for the average european.

See: Vitamin D and health: evolution, biologic functions, and recommended dietary intakes for vitamin D (293 citations)

Before I take medical advice from a newspaper, I might as well ask my local esoteric nut.

Can you provide a link to the newspaper article at least while whining about the downvotes?

Misinformation. Do more research.

Hi, author of the blog post here! Thanks for your concern. I do still stand by my claim, since more recent peer-reviewed studies have shown that up-to-10,000 IU is safe. As written in the post:

> McCullough et al 2019 gave over thousands of patients 5,000 to 10,000 IU/day, for seven years, and there were zero cases of serious side effects. This is in line with Billington et al 2020, a 3-year-long double-blinded randomized controlled trial, where they found "the safety profile of vitamin D supplementation is similar for doses of 400, 4000, and 10,000 IU/day." (though "mild hypercalcemia" increased from 3% to 9%. IMHO, that's a small cost for reducing the risk of major depression & suicide.)

So why then does Mayoclinic, etc, all say 4000 IU is the limit? I think because policy is decades behind science (this happened with trans fats), and also policymakers are much more risk-averse. (this is why in California, thanks to Prop 65, up until ~2018, there used to be a warning in every coffeehouse that coffee causes cancer.)

But thanks to your comment, I will edit the intro to note what the official max safe dose is, and that more recent peer-reviewed research shows it's too low!

I've been taking 20,000iu of Vit D daily for years, split into 10k AM/PM

Regularly have my Vit D levels checked and they are always within the upper bounds of healthy reference range

To my understanding Vitamin D is regularly underdosed. Several points:

1) There are lots of studies that correlate Vitamin D production with sunlight exposure. For example, https://pubmed.ncbi.nlm.nih.gov/20398766/ this one lands on 1/4 of a MED = 1000 IU. Of course now we have a MED definition problem, but we're roughly talking single digit numbers for a white person in midday sun in NYC to reach 1/4 of a MED.

2) If you also supplement with Magnesium, a lot of your side effects go away. Vitamin D3 depletes Magnesium absorption.

FWIW just anecdotally I took 160,000 IU per day for a few months along with 800mcg to 2mg of K2 MK-7 and about double the suggested amount of magnesium citrate. I slowly titrated up to that amount over a few months. I am not suggesting anyone else do that as I had a specific purpose slow action TPA when combined with many protease so to speak but just my own experience I did not have any of those issues. I don't know how they came up with them so I figure they are just guessing like they did with the toxic level of selenium which has a funny back story. I am back down to 5000 IU a day. Years later still none of those issues. But that is just me.

I did have one issue related to magnesium however. If I did a very high dose of magnesium taurate and a couple of other chelated forms I would have trouble catching my breath after physical exertion similar to chronic high doses of iodine. Not the end of the world but it was unnerving.

Don't anyone else do what I do. I experiment on myself more than scientists experiment on mice minus the whole dissection bit. I am just continuing some experiments from the 1900's but as I understand it AI will be learning all of those soon. Fascinating stuff really.