Vitamin D Boost contains vitamin D3, the same active ingredient present in many vitamin D pills. Studies have shown that vitamin D spray works just as effectively as taking a vitamin D pill. However, some people prefer to use a vitamin D spray because it’s absorbed quicker and more efficiently than vitamin D pills. That’s because when it’s sprayed on the inside of the cheek, it’s rapidly absorbed into the bloodstream - resulting in optimal vitamin D delivery. On the other hand, vitamin D tablets must first pass through the digestive system before they can be absorbed into the blood, which can affect how much vitamin D is absorbed.