As well as synthesize Vitamin D in skin when exposed to sunlight from April until October. It is exceptional because it can be made in the skin from exposure to sunlight. It exists in two methods which is Vitamin D2 is attained from the UV irradiation of the yeast sterol ergosterol and is establish naturally in sun exposed mushrooms while UVB light from the sun strikes the skin and humans synthesize Vitamin D3 So it is the most natural form.