7-Dehydrocholesterol (7-DHC) is a zoosterol that functions in the serum as a cholesterol precursor, and is photochemically converted to vitamin D3 in the skin, therefore functioning as provitamin-D3.
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.