I have an entire drawer dedicated to supplements. It started small, more like a pharmacological junk drawer housed in a manageable tupperware container under the bathroom sink. But through years of bodybuilding shows and powerlifting meets, bulking phases and prep cuts and a few bouts of good old fashioned self loathing it’s grown to now take up an entire towel drawer spanning five feet across and two feet deep, built straight into the bathroom wall above the drawers of extra sheets and pillowcases, and actual bath towels.
Vitamin D3 is formed by the action of ultraviolet radiation from sunlight on a cholesterol derivative (7-dehydrocholesterol) in skin. A lot of people even in warm weather climates are Vitamin D deficient. Vitamin D is metabolized in the liver and then in certain kidney cells, which results in 1,25-dihydroxyvitamin D and that is what you see in blood work to determine if you have a Vitamin D deficiency.