Asked by: Jeff Hibbard, Birmingham
No. Ordinary window glass is only transparent to wavelengths of light longer than 330 nanometres. But to synthesise vitamin D, we need UVB wavelengths between 270 and 300nm. You can get a suntan through glass, but to make vitamin D you need to be outside. On the other hand, at least 50 per cent of UVA can penetrate through glass, so skin ageing can still take place.