multivitamins are not stimulants; therefore they will not keep you up at night. being compliant is important. if it works best for you in the morning then take it with breakfast. if bedtime works better that is what works best for you. believe it or not you can actually take too many vitamins and they can build up in your body and possibly cause toxicity. this can happen especially with the "fat soluble" vitamins which are a d e and k. you definitely want to be careful and make sure that your health care provider (they may run blood work periodically) and pharmacist know everything that you are taking.
when is the best time to take vitamins in the morning or at bedtime?