Vitamins and sleep: vitamin D, B12 and the gut
Ask for the blood tests first.
Vitamin D, B vitamins and the gut
| Option | Why try it | Main caution |
|---|---|---|
| Vitamin D: a 25-OH test; if low, a daily dose the doctor sets | Cheap. Low levels go with poor sleep and apnea. NIH facts | Small trials helped self-rated sleep; the biggest found no change |
| B12 and homocysteine: blood tests; B vitamins if low or high | Many older adults lack B12. B vitamins slowed brain shrinkage. Trial, NIH facts | Weak for sleep; little memory help if homocysteine is normal |
| Dr Stasha Gominak, neurologist: vitamin D to 60 to 80, then B vitamins | Cheap. Her clinic records: better sleep in over 1,000 patients. Paper, interview (video) | Target above NIH's 50 ng/mL caution; she does not address dementia |
| ReCODE: a home sleep test, vitamin goals, melatonin 0.5 mg, gut repair | Its apnea test and B-vitamin step match the trials. ReCODE on this site | Its trial did not measure sleep; its vitamin D goal passes NIH's caution |
A guideline suggests vitamin D from age 75. Dr Gominak's view: D feeds gut bacteria making B vitamins.
Dr Gominak's steps
- Vitamin D up to 60 to 80 ng/mL, with a blood test each month.
- B12 for 3 months, only if it is low.
- Then a B50 complex for about 3 months, then a multivitamin.
Her target is above the level NIH links to possible harm, so keep the monthly tests.
ReCODE's sleep targets
7 to 8 hours of sleep, a home sleep test, vitamin D 50 to 100, homocysteine 7 or lower, B12 above 500, and no food 3 hours before bed. ReCODE on this site.
Safety lines
- Vitamin D daily, never a big monthly or yearly dose. (Big yearly and monthly doses raised falls in trials.)
- Over 4,000 IU a day only with a doctor checking levels. (The US upper limit.)
- On a thiazide water pill? Ask before vitamin D. (Together they can raise blood calcium.)
- B vitamins in the morning. (At bedtime, a B complex worsened sleep in a trial.)
- Tingling or numb feet on B pills? Stop, and call the doctor. (B6 can damage nerves; the US limit is 100 mg a day. A B50 holds 50 mg.)
The blood tests to ask for
- Vitamin D, B12, folate, homocysteine; iron if the legs are restless; MMA if B12 is borderline. (Name the dementia diagnosis: one Medicare region accepts it for B12, folate and homocysteine. Covered tests usually cost you nothing.)
- Vitamin D may not be covered. (Another region needs a reason like osteoporosis, not sleep or dementia. Quest's cash price: $75 plus a $6 fee.)
Our biases, out loud
We lean on big trials and mainstream US sources, and this page was researched with an AI assistant that leans the same way. Clinical reasoning and what helps people now can get undervalued.
Checked 14 October 2026. Sources.