Can I Get Vitamin D Through a Window?

Virtually all commercial and automobile glass blocks UVB rays. As a result, you will not be able to increase your vitamin D levels by sitting in front of a sunny window, though much of the UVA radiation will penetrate the glass and may be harmful.

Can you get vitamin D from the sun behind a window?

The body cannot make vitamin D when exposed to the sun's rays through a window as the glass blocks the sun's UVB rays. Some people's skin is less able to make vitamin D than others.

Do you have to be in direct sunlight to get vitamin D?

From about late March/early April to the end of September, most people should be able to make all the vitamin D they need from sunlight. The body creates vitamin D from direct sunlight on the skin when outdoors. But between October and early March we do not make enough vitamin D from sunlight.