Vitamin D

Vitamin D is a fat-soluble essential vitamin that the skin synthesizes when exposed to the sun.

Also known as: Cholecalciferol, Ergocalciferol

examine.com

ConsumerLabs

Wikipedia

pubMed

https://www.lifeextension.com/magazine/2016/1/why-isnt-everyone-supplementing-with-vitamin-d/page-01

https://chriskresser.com/vitamin-d-the-new-super-nutrient/