I blogged earlier about what I called a “stunning discovery”: Primal Girl found her sleep got much better when she started taking Vitamin D first thing in the morning (= soon after she got up) rather than mid-afternoon. This suggested that Vitamin D acts on your circadian system similar to a blast of sunlight. (More evidence and discussion here.) In his blog, Joseph Buchignani reports another experience that supports the idea that you should take Vitamin D first thing in the morning:
I picked up a bottle of Vit-D and Calcium. Dosage of Vit-D per pill was 1.6ud. Per the instructions, I took 1 at morning and 1 at night. I began this regimin on the night of the 24th of November. It’s now the night of the 25th of November, and my circadian rhythm is completely fucked. . . . I’m fully awake now (12:30 AM), and I probably took the last dose of Vit-D around 7-8 PM. . . . I woke up with dark eye rings on the morning of the 25th. My energy level did not rise as it should have, but sort of meandered in the middle, before finally tailing off. Stress levels and depression were both elevated. I got little productive done.
Yesterday I started taking Vitamin D first thing in the morning. I took 2000 IU of Vitamin D3 at 8 am. In the afternoon I felt more energetic than usual. The next morning (this morning) I woke up feeling more rested than usual. This also supports Primal Girl’s experience.
Let me repeat: first thing in morning. If you wake up before sunrise, take at sunrise (say, 7 am). Sunlight has a considerably different effect on your circadian system at 7 am than 10 am. (Look up circadian phase-response curve and especially the work of Patricia DeCoursey if you want to understand why three hours makes a big difference.) I have two bottles of Vitamin D. Neither mentions time of day. Both say take with meals.