Vegetarian here who recently started taking multi vitamins + extra vitamin d + k2 (after being diagnosed with a severe vitamin d deficiency). I also get less tired since and even more so my sleep has improved drastically within about 2 months. I fall asleep _so_ much faster. Usually 10 minutes now instead of an hour and I also sleep through most nights instead of waking up 6 or 7 times for no reason for the past 10 years. I haven't changed other variables (I think) but so far I am happy with the results. Also purely anecdotal.