Vitamin D - Wikipedia, the free encyclopedia

Vitamin D is a group of fat-soluble prohormones, the two major forms of which are vitamin D2 (or ergocalciferol) and vitamin D3 (or cholecalciferol). ... http://en.wikipedia.org/wiki/Vitamin_D 

Dietary Supplement Fact Sheet: Vitamin D

Vitamin D is a fat soluble vitamin that is found in food and can also be made in your body after exposure to ultraviolet (UV) rays from the sun. ... http://dietary-supplements.info.nih.gov/factsheets/vitamind.asp 

Is Vitamin D a "Missing Link" in PCOS?

A "forgotten vitamin" plays a crucial role in dealing with PCOS and improving your health.   It's vitamin D, the "sunshine" vitamin. Unfortunately, women with PCOS tend to have lower than adequate vitamin D levels.   Optimal vitamin D levels are important...