Vitamin deficieicies can lead to a wide variety of symptoms ranging from minor to very major.   As with any new supplement or medications, make sure that you keep track of how you feel and your symptoms once you begin something new. 

Many times the reason someone is deficient in a vitamin or mineral is due to their gut health, so taking liquid vitamins allows your nutrients to be absorbed into the bloodstream within a couple of minutes. 

Prior to starting a supplement, make sure you understand the pros and cons of that supplement.  Not everything is good for everyone.