Vitamin D - Not a Magic Bullet, but Vitamin D Deficiency is a Poison Arrow

I found this presentation by Karl Pfleger of interest. I think I’ll have my vitamin D levels tested the next time I do bloodwork.

Karl is a well known Ex-Google guy and now a leading Longevity Angel Investor in the Bay Area. He also maintains a good resource list website here:


Vitamin D presentation for personal longevity group.pptx.pdf (1.4 MB)

Link to source document:


What a treasure trove of information, thanks for sharing.

@RapAdmin You need to Karl to add this site to the blogs tab.

I take 6,000 IU/day (D3/k2), at night before bed. My levels are in the 200 nmol/L range. My FMD wants a level at least 175.

What’s fascinating about Vitamin D is you can take one time injections and pretty much cover off your Vitamin D needs for at least 3 months+. Oral compliance, especially older folks, is very low.


I vacillate between using 5000 IU and 1000 IU daily. It seems that public opinion changes from taking more to taking less back to more and so on… Which amount do you think is better in general?

I have also heard that you shouldn’t take D3 and K2 together at the same time as they interfere with each other’s absorption. There should be a 2-hour interval between the two. Is this true? Lots of supplements bundle D3 and K2 together so it seems inherently wrong, but then I have seen some supplement bundling that doesn’t make sense. My solution is to take D3 and other fat soluble vitamins in the morning and K2 at night.


I exchanged some emails with a Vitamin K2 vendor…there is NO impact of absorption on combining.

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Thank you MAC. When you read the literature and come across opposing opinions, it’s good to have strong evidence for one or the other. This is strong enough to push me into the other camp of not worrying about when I take K2. Was there any negative to taking the two separately and spaced apart?

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Karl does a good job picking the holes in the paper.

I checked with Dr Gundry, huge AD prevention patient population…he wants his patients around 100 ng/mL. His own is 120 ng/mL. I need to take some more…I am still in the therapeutic window!