Vegan vitamin D supplements are safe for vegans and are created from lichen. Lichen is a cyanobacterium also known as blue-green algae. It tends to be classed as algae but is actually a symbiosis between fungi and algae. Another plant-based source used for vegan vitamin d supplements is mushrooms. Non-Vegan vitamin D supplements are created from lanolin. Lanolin is an oily substance (sebum) that is secreted from the glands of wool-bearing animals (predominantly sheep) to condition their wool and protect them from extreme weather.