Vitamin D3 in Morning Has Ambiguous Effects on Sleep and Energy (Story 15)

A reader named Murray Love about Vitamin D3 and sleep that at least sounds negative:

As a counterpoint [to this post ], I’ve been taking 4-5,000 IU of D3 for a couple of months now, and while it might be making me feel better in other ways (more vital, upbeat, and energetic), it has coincided with a stretch of poor sleep. I have what they (hilariously) call “terminal insomnia” that is, I usually have no trouble at all falling asleep, but I wake regularly at night and am permanently awake very early, often from 4:30am onwards. This has been a periodic problem for a few years now, though this stretch is notably tolerable, for some reason.

I asked for details: