(source) Sunscreen can reduce the sun's adverse effects, but there are concerns that it might inhibit the body's production of vitamin D. In a new study, however, investigators recorded an increase of vitamin D in participants during a week of cloudless weather, with very high UV index, even when sunscreens were used properly and prevented sunburn.
Gee, it's almost like they knew this when they told you to stay inside...
Nope!
According to this video, sunscreen blocks absorption of D. Sorry.