evidence: Sheep secrete lanolin through their glands to help protect their wool coats from the environment by making them water-resistant. This secreted grease not only protects the wool coats of sheep, but it also contains the same vitamin D used in the vast majority of artificially manufactured vitamin D supplements on the market today. Vitamin D is extracted from sheep’s wool by squeezing or rolling the wool until it excretes a yellow and waxy substance – sheep grease. After which it is heavily processed and concentrated with synthetic chemicals until it’s consolidated into one hard-to-swallow pill for yours truly.