I take Vit D (4000iU daily) which keeps my levels in the normal range, however, for me supplementation with B vitamins is a problem. Vitamins B12, B6 and folate will all give me insomnia after about a week.....I'll be awake literally all night. I "discovered" this twice by accident when taking multi vits, and since then have rediscovered twice more when nutritionists couldn't believe it was so, and got me to try again. Even the fortified plant-based yogurts will give me insomnia if I over-indulge in them. Keto will make me insomniac too, so my carbs have to steer a careful course between triggering high BS and insomnia.