What is the source of the D3 in SunDew?

Sundew Transdermal Vitamin D Crème contains vitamin D3 from lanolin, which occurs naturally on the wool of woolly animals, such as sheep. D3 is the same type of D vitamin created in your body when you expose your skin to sunlight, and this transdermal absorption of vitamin D can boost whole-body immunity. D3 is approximately 87 percent more potent in raising and maintaining vitamin D concentrations, and produces 2- to 3-fold greater storage of vitamin D than does D2.