Vitamin D4 is primarily used in research settings to study the effects and mechanisms of vitamin D compounds. It helps scientists understand the role of vitamin D in calcium absorption, bone health, and immune system regulation. Additionally, it is utilized in the development of dietary supplements and fortified foods to address vitamin D deficiencies. Its application in agricultural practices includes enhancing the nutritional value of animal feed, promoting healthier livestock. Vitamin D4 also serves as a reference compound in analytical chemistry for the identification and quantification of vitamin D analogs in various samples.