* Science-Based Nutrition * Dietary Supplement Vitamin D3 (cholecalciferol) is a nutrient that is critical to many bodily functions. Vitamin D3 is beneficial for supporting bone health, immune wellness, cardiovascular function, and cellular metabolism, among others. Mounting research is highlighting the ever-increasing benefits of optimal vitamin D3 status. Vitamin D3 is known to interact with over 200 different genes and thus plays a crucial regulatory role as a metabolic activator for a multitude of metabolic processes.