so, when i get sun on my skin behind my window, i 'm not producing vitamin D?...
That's correct! When you're sitting behind a regular glass window, your skin is not producing much, if any, vitamin D. This is because the UVB radiation that triggers vitamin D production is blocked by the glass.
This is an important consideration for people who spend a lot of time indoors, especially during the winter months when sunlight exposure is limited. In these cases, vitamin D supplements or fortified foods may be necessary to maintain adequate levels of vitamin D in the body.
It's also worth noting that UVA radiation, which is not blocked by glass, can still penetrate windows and cause skin damage over time. So it's important to protect your skin from the Sun even when you're indoors, especially if you're sitting near a window.
