Light therapy is often incorrectly likened to the secretion of vitamin D. 

Indeed, vitamin D is synthesized by cells in the skin when these are in contact with UVB and UVA which are naturally found in sunlight. A light therapy lamp, if it is certified, emits a light whose spectrum is completely devoid of ultra-violet. 




That is why the skin does not emit vitamin D during a light therapy session.

On the other hand, the exposure of your eyes to a light therapy lamp has beneficial effects on the regulation of your natural rhythms and your energy level.