Effect of Vitamin D3 on My Sleep

Seth Roberts

I have blogged many times about biohacker Tara Grant’s discovery that she slept much better if she took Vitamin D3 in the morning rather than later. Many people reported similar experiences, with a few exceptions. Lots of professional research has studied Vitamin D3 but the researchers appear to have no idea of this effect. They don’t control the time of day that subjects take D3 and don’t measure sleep. If the time of day of Vitamin D3 makes a big difference, measuring Vitamin D3 status via blood levels makes no sense. Quite likely other benefits of Vitamin D3 require taking it at the right time of day. Taking Vitamin D3 at a bad time of day could easily produce the same blood level as taking it at a good time of day.

I too had no idea of the effect that Grant discovered. I had taken Vitamin D3 several times — never in the morning — but after noticing no change stopped. I tested Grant’s discovery by taking Vitamin D3 at 8 or 9 am. First, taking it at 8 am, I gradually increased the dose from 2000 IU to 8000 IU. Then I shifted the time to 9 am. The experiment ended earlier than I would have liked because I had to fly to San Francisco.

When I woke up in the morning I rated how rested I felt on a 0-100 scale, where 0 = not rested at all and 100 = completely rested. I’d been using this scale for years. Here are the results (means and standard errors):

Vitamin D3 had a clear effect, but the necessary dose was more than 2000 IU. If Vitamin D3 acts like sunlight, you might think that taking it in the morning would make me wake up earlier. Here are the results for the time I woke up:

There was no clear effect of dosage on when I got up. Shifting the time from 8 am to 9 am may have had an effect (I wish I had 3 more days at 9 am).

Many people have reported that taking Vitamin D3 in the morning gave them more energy during the day. I usually take a nap in the early afternoon so I measured its effect on the length of those naps:

Maybe my naps were shorter with 6000 and 8000 IU at 8 am. It’s interesting that 4000 IU seemed to be enough to improve how rested how I felt but not enough to shorten my naps.

What do these results add to what we already know? First, the large-enough dose was more than 2000 IU. (A $22 million study of Vitamin D3 is using a dose of 2000 IU.) The dose needed to get more afternoon energy may be more than 4000 IU. Second, careful experimentation and records helped, even though many people found the effect so large it was easy to notice without doing anything special. For example, these results suggest the minimum dose you need to get the effect. Three, these support the value of supplements. Many people say it is better to get necessary nutrients from food rather than supplements. However, supplements allow much better control of dosage and timing and these results suggest that small changes in both can matter. I cannot imagine this effect being discovered with Vitamin D3 in food.

23 thoughts on “Effect of Vitamin D3 on My Sleep”

  2. Hi Seth, I love your blog and have a couple questions. If taking vitamin D supplements in the morning is beneficial, then does that suggest that eating vitamin-D-rich animal/sea foods in the morning might also be beneficial?
    Seth: No I don’t think it suggests that…I think there is too little Vitamin D3 in them.
    What do you think of the report by Mira and Jason Calton, authors of Naked Calories, that they traveled around the world to observe over a hundred traditional peoples in what they called The Calton Project (https://caltonnutrition.com/calton-project.aspx) and found that traditional peoples tend to eat a meal in the morning (https://www.fatburningman.com/best-seller-naked-calories-mira-calton-jayson-calton-interview)?

    Seth: That’s very interesting. I’ll try to find out more about it.
    Reply
  3. Dave Asprey of Bulletproof Executive mention that the body can store D3 for up to a week. This was in reference to going on a trip and not wanting to take along a bottle of D3. You can take a weeks worth (25-50K IU) at one time and be good to go – if you’re going to Hawaii and laying on the beach all day, you’re doubly good to go.
    There doesn’t seem to be an upper limit on D3 supplementation. However, tanning could be argued that it is a self regulating limiting factor (the tanner you are the more sun you need to produce the same amount of D3).
    I’ve read that the optimal dose is 1000 IU per 25 lbs of body weight – I’m around 130 and take 5000 IU/day – as soon as I get up – plus I spend as much time in the sun without sun screen as possible because I also heard or read that the type of D3 produced from the sun is slightly different from the supplements (and I just like being out in the sun).
    When it comes to sleep quality, and testing some protocol, I think it would be interesting to hook yourself up to a sleep monitor and compare the results from the monitor to how you feel when you wake up and how you perceived your nights sleep – restless, calm, don’t remember a thing, etc.
    I would test it for some period of time where I didn’t see the results from the monitor until the end of the test. I think that would give you a clearer picture of what your mind was doing compared to how you perceived your sleep.
    Anyway, the sun is out, so I gotta go. Cheers
    Reply
  4. Seth, if you have an iPhone, there is an app called “sleep cycle” that will track your restlessness during sleep. It uses the phone’s accelerometer as a proxy for soundness of sleep.
    (While the app is designed to wake people up at the best point in their sleep cycle– thus maximizing their feeling of being rested – it also has a “no alarm” mode that would allow you to use it just for its sleep statistics display.)
    Reply
  5. I’m interested in the best way to track one’s sleep quality. I know Dr. Roberts and others use “sleep-wanted” rating first thing in the morning, but when trying this plus an end-of-day rating for average fatigue, I felt sleep-wanted was sometimes wildly off.
    However, in some ways it’s easier to jot down a number first thing in the morning than review the whole day’s energy level at the end of the day.
    Anyone have any other tips for “pen-and-paper” sleep quality measuring?
    Reply
  7. I am also doing some experiments with it, which I will report soon. I have a question though: what is the maximum recommended dose for D3? Taking over 4000 UI for long periods of time, say years, seems a very large dose to me: I was wondering how safe it is. Cheers,
    Seth: Different places recommend different dosages. Some people say 2000 IU/day is dangerous. Some people have taken 10000 IU/day for a long time with no problem. Given the time of day effect and the huge importance of good sleep for good health, all previous studies (which did not control for this) are suspect. For example, maybe 2000 IU is only dangerous if you take it at night.
    Reply
  8. Seth, are you still taking the tablets or have you switched to gel-caps? Supposedly there is a big difference in absorption between them…

    Seth: this study was done with tablets. Now I use gelcaps…what is the difference in absorption?
    Reply
  9. It was an interesting podcast, so I listened to it again and my memory was a bit off. The Calton’s visited over 100 countries (with peoples of all types), rather than over 100 traditional peoples. Here is what Jayson said about morning meals:
    36:36 “When we traveled around the world, this is what we found: people basically ate in the morning, they would kind of snack on something small in the afternoon and then they’d eat again at night.”https://www.fatburningman.com/best-seller-naked-calories-mira-calton-jayson-calton-interview
    This and other reports cause me to question whether Stone Age peoples really did mostly skip “breakfast.” I suspect that if they had food in the morning before going out to hunt/gather, they would eat some of it (not knowing about any theories about better sleep from skipping breakfast), and if they didn’t have any food, they didn’t. Also, I doubt they would pass up choice berries, honey or other preferred available foods they came across just because it was morning. This doesn’t mean that eating “breakfast” is necessarily optimal in today’s world, of course, and some food would probably be gathered and brought back to camp for the main feast in the evening and the foods closest to camp would be used up first, forcing longer-distance foraging and later meal times.
    Seth: I wonder what they ate in the morning and when, relative to when they got up. I found that eating within about 3 hours of getting up was a bad idea. So an early breakfast would be bad but brunch is okay.
    Reply
  10. Yes, I wondered about that too and did some searching and found some indication that centuries ago people tended to eat breakfast around 9-10 am (https://www.foodtimeline.org/foodfaq7.html), rather than earlier. On the other hand, my understanding is that hunters and fishers tend to rise early. If true, then if I were a hunter, I’m thinking I would want to grab a quick bite of leftovers upon rising, so I wouldn’t have to carry much or any food while hunting/fishing. Maybe meats and fish are less of a problem when consumed early in the morning than agricultural foods (there is some evidence for this –https://www.gnolls.org/2181/the-breakfast-myth-part-2-the-art-and-science-of-not-eating-breakfast)? Then again, going back further in time, in pre-weapon and pre-fire days I doubt hominids would have left much food uneaten in their camps overnight, so as not to attract predators. Perhaps there hasn’t been enough time to adapt to morning meals?
    Seth: I listened to part of the podcast and heard that these indigenous people did not store food but ate it soon after they gathered it. That would rule out eating soon after you wake up. To get food they must have had to walk a considerable distance.
    Reply
  11. Dr. Davis heartscanblog claims that some people fail to absorb the vitamin D from tablets as well as the vitamin D from gelcaps. This is based on his clinical experience tracking the response of serum vitamin D in response to supplementation.
    Seth: Thanks, that’s good to know. I found that tablets worked.
    Reply
  12. Hi Seth, thanks for your reply. I understand and agreed with your point regarding previous studies. Yet, “Some people have taken 10000 IU/day for a long time with no problem” is still a little too uninformative (though I see there can’t be more precision as of now). My follow up questions is this: can we be tested in any way, such as take a blood test, to detect overdosages? I find it curious that apparently nobody is much worried high intake. Cheers,
    Seth: “Nobody is much worried high intake”? I am. I use the minimum dose that produces the sleep improvement.
    Reply
  14. https://blog.vitamindcouncil.org/2011/11/08/does-it-matter-how-you-take-vitamin-d/“Does it matter how you take vitamin D”
    Summary: “The fact is that the studies are so conflicting, and the 25(OH)D measurement techniques are so variable, that it simply does not matter if you take vitamin D in oil or as a powder, it does not matter if you take food with your vitamin D, or on an empty stomach. What matter is that you take enough so that you obtain vitamin D levels of 50 -60 ng/ml”
    Reply
  15. I have found over the last 5 months that there is an interaction between D3 (in the morning) and food intake in the evening. I need 3-4000IU D3 (gel caps) to enable me to sleep all night. However, a late (post 8pm) evening meal will disturb this, especially when carbohydrates – as in a pudding – are involved. Then I will wake again, and will not easily return to sleep.
    This suggests that the Leptin system in involved, (see Jack Kruse’s work) and presumably overrides the D3 effect.
    However, without the D3 to enable me to sleep most of the time, I would not have noticed the effect of the late evening meal. Anyone else have similar observations?
    Seth: I don’t understand the connection with leptin. I think your results suggest that D3 and late meals push in opposite directions. D3 pushes you toward sleeping through the night, late meals push you in the other direction. As for “without the D3 to enable me to sleep…” look up floor and ceiling effects.
    Reply
  16. As it happens, I finished my own experiment & analysis on Saturday, and as far as my data is comparable to Roberts’s, I found the same thing – no effect on anything but restedness/’Morning Feel’:https://www.gwern.net/Zeo#vitamin-d-at-morn-helps
    Isn’t that strange? You’d expect the mood improvement to be mediated by sleeping better on one of the other metrics – sleeping more, waking less, etc. – but apparently not. Are there any neurobiologists or circadian specialists around?
    Reply
  17. Seth, what’s going on with the “Rested (percent)” x-axis? Are you really measuring significant difference in restedness feelings only around 98.9% – 99.5% on a scale of 0-100%? Or is there some mistake with the labeling?
    Seth: The label is correct. If you think those differences are too small to tell apart, subtract them from 100. The implication that I wake up each morning feeling very rested is true. A psychologist named S. S. Stevens spent his whole career showing that people were quite good at attaching numbers to “sizes” (he used the word “magnitude”) of internal states, such as loudness. Here I am attaching a number to how tired I feel when I wake up.
    Reply
  18. Hi Seth
    I just found this blog and it is very interesting. I am amazed about this topic.
    I have struggle with sleep problems for over 10 years and have tried almost everything. But this is complete new to me.
    I take 2000 D3 in the morning since some years back and it have worked wonders with the mood in the winter.
    May I ask to have some advice on how much I should take in the morning, and do I need to take something more. As I usually take Magnesium and calcium in the evening. Or is it posted in more detail earlier that I have missed
    Seth: I found that 2000 IU had no effect on me but 4000 IU and higher doses did have an effect. Now I take 5000 IU D3. Try different times in the morning: 7 am, 7:30 am, 8 am, etc. Figure out which works the best.
    Reply
  19. Thank you Seth !
    I have taken 6000 this morning, as I have earlier inregular been taken 4000 and have not notice any diffence.
    Reply
  20. Just come across a few articles by Stasha Gom­i­nak, M.D.
    She writes that ideally the D25OH blood level should stay between 60 and 80 ng/ml to sleep perfectly.
    She also writes that “sleep (is) just as abnormal when it goes over 80, as it does when it’s under 50.”
    https://drgominak.com/vitamin-d
    https://drgominak.com/sleep
    Some food for thought there, something to keep an eye on if/when your 25ohD gets above 80 ng/ml
    Seth: Dr. Gominak’s emphasis on blood levels — although conventional — doesn’t make sense given the enormous importance of time of day. Maybe a blood level of X (e.g., 60) is good if you take your D3 at the right time of day and bad if you take it at the wrong time of day.
    Reply
  21. @ Gav
    Thank you so very much for the link on May 17th on D3- Ot was very useful and interesting. Now it really make sence too my and I undertand a lot of my dougther al well
    Reply
  22. I have also found the time of day to be important.
    & I have tested the theory that taking D3 in the evening before bed may disrupt sleep. In one experiment i took 2000 IU before bed & it felt like i was awake all night….I will not be repeating that experiment.
    I wonder if Dr. Gominak’s upper limit of 80 ng/ml may also have some validity; ie. if ones serum 25ohD was slowly rising from the morning supplementation over time (months) until it finally got over 80 ng/ml, then sleep may become disrupted again, even with the morning D3 supplementation.
    That said, i would presume that most peoples serum 25ohD is nowhere near 80 ng/ml.
    That reminds me, i must get mine tested again, as we head in to Winter here in the southern hemisphere.
    Reply
  23. @ Gav
    I have read the Gominak links once more, they are really good and gives a lot of answers. I need to find a place to have my level checked to.
    Reply

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