Most sunscreen block most of vitamin D and let the suntan wavelengths to get to the skin
Wanted: not block UVB, but block the UVA
Perhaps sunscreen pills being sold in 2012 will have a spectra more like wanted
Charts from http://www.detertec.com/sun_radiometry.html
Red = sunlight in space, Green = sunlight in Equator
Red = sunlight in space, Green = sunlight in Equator Blue = sunlight in Albuquerque, NM
Red = sunlight in space, Green = sunlight in Equator Blue = Vitamin D action spectra
No vitamin D is produced in UVA-1 or UVA-2
Red = sunlight (probably on ground); other lines = amount of light filtered thru different sunscreens
We see than many sunscreen products do NOT block the upper UVA
This might be the reason that as people feel that they can stay out in the sun longer they get more cancer while getting less vitamin D
See also VitaminDWiki
- Overview UV and Vitamin D
- Sunscreens which do not block UVB which makes vitamin D
- UV spectra to produce vitamin D which has the following graphic