Two minutes sun is all you need for vitamin D (not)
Australia is still insisting on their slip, slop, slap campagn
From ABC News WA Australia
"[the sun] also it stops producing vitamin D after the first few minutes in the sun. It shuts down.
"It's like a natural overdose protection."
Note: I have not seen a single study which even hints to shutting down production of vitamin D in a few minutes.