Vitamin D3 in Morning: 4000 IU Better Than 1000 IU (Story 20)

Daniel Lemire, a Canadian computer science professor, left the following comment here

I have irregularly taken 1000 UI  in the morning for years with no noticeable effect.

For about two years, I have had poor sleeping patterns characterized mostly by the fact that I tend to go to bed at 1am or later (and I get up around 7:15 am [woken up by an alarm clock]). Whenever I would try to go to bed earlier, I would simply fail to fall asleep.

After reading this blog, I increased my intake of D3 to 4-5,000 IU. I’m now falling asleep about an hour earlier. This could be a placebo effect, of course, but I consider it a very significant improvement.

It is unclear whether I have more energy. I don’t know how to measure such an effect. I expect that I’m less irritable, but that’s a side-effect of getting more sleep.

I asked him for details.

Tell me about yourself.

I’m in my 40’s. I enjoy a flexible schedule and often work from home.

You write: “For about two years I have had poor sleeping patterns characterized mostly by the fact that I tend to go to bed at 1 am or later (and get up around 7:15 am [woken up by an alarm so that he can eat breakfast with his family and walk his kids to school]). Whenever I would try to go to bed earlier, I would simply fail to fall asleep.” You mean you are still tired when you get up? You want to sleep longer but are unable to?

I was getting about 6 hours of sleep, and yes, I was still tired when I got up. I’m less tired now that I am getting around 7 hours of sleep.

“I tend to go to bed at 1 am or later”. What was the average (median) time of going to bed? When you went to bed at this time (“1 am or later”), how long would it take you on average (median) to fall asleep?

The median is 1 am. I fall asleep immediately. I don’t go to bed unless I know I will soon fall asleep: I tried to go to bed earlier, but it made me feel worse about my insomnia and I did not get better sleep. I tend to stay up until I feel like I must go to bed.

“After reading this blog, I increased my intake of D3 to 4-5,000 IU.” How many days have you been at the new dosage?

2 weeks +/- 3 days.

Was this the only change?

Yes. As far as I can tell. The time did not change. It is around 7:30 am. Soon after I get up. Before coffee.

“I’m now falling asleep about an hour earlier. ” What time (median) is that? How long (median) does it take you to fall asleep? What time are you now waking up?

I now fall asleep around midnight. I just instantly fall asleep. So I am getting approximately 7 hours of sleep.

“I expect that I’m less irritable.” You’ve noticed that you’re less irritable?

Yes. I feel less irritable.

What brand and formulation (e.g., capsule, gelcap, tablet) of D3 do you take?

Walmart house brand (“equate”). Tablets, 1000 IU/tablet. I take 4, sometimes 5. (Median is 4.)

10 Replies to “Vitamin D3 in Morning: 4000 IU Better Than 1000 IU (Story 20)”

    1. Seth, have you considered two-stage sleep? We appear to be naturally inclined to sleep in two, four-hour stages per night, with a waking period in between, according to modern studies, historical references, and modern day hunter gatherer tribes:

      I am not so sure. What if all those studies involved people who didn’t stand much (say, less than 4 hours/day) but long ago people stood much more (say, more than 8 hours/day)? And if you stand a lot the two-stage structure disappears? So it is not so clear what we are “naturally inclined” to do. I admit however that I can get a lot done after I wake up early in the morning but before I later fall back asleep…so it is not so clear there is anything wrong with this two-stage structure.

  1. Perhaps the methods that you have used to combat your early-waking have been interfering with our natural tendency to have twin sleeping-cycles. Did you see the side bar in the BBC link?

    When segmented sleep was the norm:

    “He knew this, even in the horror with which he started from his first sleep, and threw up the window to dispel it by the presence of some object, beyond the room, which had not been, as it were, the witness of his dream.” Charles Dickens, Barnaby Rudge (1840)

    “Don Quixote followed nature, and being satisfied with his first sleep, did not solicit more. As for Sancho, he never wanted a second, for the first lasted him from night to morning.” Miguel Cervantes, Don Quixote (1615)

    “And at the wakening of your first sleepe You shall have a hott drinke made, And at the wakening of your next sleepe Your sorrowes will have a slake.” Early English ballad, Old Robin of Portingale

    The Tiv tribe in Nigeria employ the terms “first sleep” and “second sleep” to refer to specific periods of the night

    1. you didn’t like my first example, okay, let me give you two more: 1. Is whatever language the Tlv speak likely to be the very first human language? 2. Is whatever diet the Tlv eat likely to be the very first human diet (or even the diet of 100,000 years ago)? I don’t mean that you’re wrong — just that I am less convinced than you.

  2. So you think that perhaps even 500 years ago, we were eating and acting outside of the natural behavior of our ancestors, which was (and is) disrupting our sleeping patterns? Seem plausible to me.

    Seth: Yes, that’s what I think. One reason the Tlv may have segmented sleep is that they don’t eat enough animal fat.

  3. I am skeptical about most claims about what might be considered normal human sleep. For example, the entertaining and fascinating book “Don’t Sleep, There are Snakes” is one of several accounts I have come across where hunter-gatherers slept according to odd schedules. And the health blogs constantly talk about keeping your room pitch-black so as not to affect melatonin levels. And yet didn’t hunter-gatherers camp under full moons?

    Seth: yeah, and did they or didn’t they sleep in the shade of trees? and did they or didn’t they cover their eyes while they slept? I don’t think we’ll know the answer to these questions any time soon. However, my many attempts to make my sleep deeper did eventually improve my ability to fight off colds.

  4. I can see how this can happen. For most people 1,000 i.u is not enough and it has been proven in many case studies. The ideal amount of D3 consumption can range from person to person, but it should be around 5,000 i.u – 10,000 i.u. I was reading an aricle on: and it basically explained this is due to changes in society; electricity, working inside for long hours, sunscreen..etc

    Kirk, it is recommended to sleep in complete darkness. Any form of light immediately signals to your body to stop producing melatonin. However, you did bring up a very valid point that I have not yet studied. I’ll have to look into that.

  5. Has anyone else noticed this?

    I have been taking 4 x 1000 u in the mornings for the past 6 weeks. In the past 2 weeks, 4 people have asked me if I’ve been on holiday as I appear ‘tanned’ and healthy.

    I live in Canada. We have limited daylight at this time of year and I do an office job.

    Blood pressure is okay and I eat mostly paleo, and I have had no other significant lifestyle changes in the period.

    Has anyone else seen similar effects?

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