Experiment: Vitamin D

How I am experimenting my way to my ideal Vitamin D supplementation protocol.

Vitamin D is key to maintaining bone health. It is also important for immune function and reduces the risk and severity of diseases like multiple sclerosis, heart disease, flu, and COVID-19. It has an impact on mental health as well, assisting in the regulation of mood and decreasing the risk of depression. 

So what are ideal Vitamin D levels? When reference ranges are depicted in lab test results, those reflect the values from the general population. This does not always equate to optimal levels in each individual. 

There are several differing opinions on optimal Vitamin D levels; my research led me to target a level of 50 ng/mL or above (you can read a helpful summary here). 

Many of you have heard that if you get 10-30 minutes of sun exposure a few times a week, your vitamin D levels should be ok. I live in sunny LA and spend a good amount outside (running, taking out the kids, etc.). I wondered if my Vitamin D levels would be adequate from “just” deliberate sun exposure; I suspected not, as I’ve previously had low levels, but how would I know if I didn’t try?

So in early 2021, I stopped taking supplements for around 6 months to get back to my baseline. In June 2021, I got labs done, and my Vitamin D level was 20. 

Lab reference ranges are in the 30-100 range, so my result of 20 was low even by these standards, never mind optimal ranges for healthy adults. So no, for whatever reason, sun exposure alone was not adequate for me to achieve high enough levels.

Vitamin D is fat-soluble and releases fairly slowly. I had been reading about periodic injections as opposed to daily oral supplementation. I had experience with self-administered injections using peptides, so the shots didn’t bother me, and I decided to try intramuscular shots of 100,000 IU every two weeks (~7k IU a day). This was an easy protocol to stick to; the injections were done with insulin needles and didn’t really hurt.

When I retested in November, my level was 42. Better! But I wanted to try to get into the 70-90 range.

I decided to increase my dose, but I had also been reading about the importance of including Vitamin K2 with D3 because of its role in calcium transport to bones (I should also note that, in addition to Vitamin K, it’s important to get adequate amounts of Magnesium and Vitamin A to ensure that Calcium is being used in the right way. I’ll be writing a follow-up post on this). Also, taking high doses of Vitamin D without including K can increase one’s risk of arterial calcification. 

For the next phase of my experiment, I decided to stick to the shots but add oral 5k IU D3 plus 90 mcg Vitamin K2 about 5 times a week, equating to ~9k IU a day.

I retested in March; my level was 73. Pretty much ideal. I had gotten into a good routine with oral supplementation, but honestly, administering the shots was getting old.

So for the next iteration of the experiment, I decided to drop the shots, take 15,000 IU around 5 times a week, and increase Vitamin K2 to 270 mcg Vitamin K2. I took 5k IU D3 with 90mcg K2 with my morning shake and the remaining amount with my lunch.

I just did my latest labs, and my level was 106 ng/mL. Higher than necessary, and given there is some risk in taking larger doses, I have decreased my dose. Given my prior iterations of this experiment, it seems my ideal dose is around 7k IU of Vitamin D a day.

My new protocol, and hopefully final phase of this experiment, is 10k IU Vitamin D 5 days a week. I’ve also switched to Thorne’s 3K supplement, which has multiple forms of Vitamin K (I’ll write another post on Vitamin K in the coming weeks). I think this is going to be the ideal combo for me, but I won’t know until I stabilize and test again. I’ll update you all again in a few months!

If I were to do this all over again. I think I could have zeroed in on my ideal dose with two experiment iterations (please remember I’m not a medical professional, so this isn’t meant as medical advice for anyone else):

- Test levels, a baseline is needed 
- If levels are low, start with 5k IU a day of D3 and around 100 mcg K2.
- Maintain protocol for 3-4 months, and test again.
- If levels are still lower than ideal, increase to 7-10k IU a day of D3 and around 200 mcg K2.
- Maintain protocol for 3-4 months, and test again.

At this point, I would have likely been in the mid to upper ranges of reference levels, and have a good sense of how variations in dose affect my levels.