The most valuable player in your supplement line up, Vitamin D3 is an essential vitamin that has a role in everything from supporting the nervous system and immune function, to aiding in the absorption of calcium. This sublingual spray is easily absorbed and delivers 3,000IU per dose. Why it works: Boosts the immune system: Vitamin D interacts with cells responsible for fighting infection, and a number of studies have found that supplementing with Vitamin D may reduce the risk of respiratory tract infections. Aids calcium absorption: Vitamin D is crucial for the absorption of calcium, and is believed to help with joint and bone pain as well. Supports mental Cognitive health: Important for cognitive function, people with low vitamin D levels have been found to be at a greater risk for developing depression. You Nue Use morning or night. Spray 3x directly under the tongue. Use with all your supplements, daily. Note that the supplement is vegetarian but not vegan, as the Vitamin D is sourced from sheep's wool lanolin.