process
Sunlight
UVB exposure can trigger vitamin D synthesis in uncovered skin.
About Sunlight
Season, time of day, cloud cover, skin pigmentation, age, and other factors change UVB exposure and synthesis. Those variables make a single safe exposure target unreliable.
Where does vitamin D come from—and where does it go?Related topics
Sunlight helps skin make vitamin D.
UVB radiation can convert a compound in uncovered skin into previtamin D3, which then becomes vitamin D3.
References
Source-checked local draft.
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