I have a small blacklight installed in my home, and I turn it on a couple of hours a week when I watch TV. It definitely makes me feel more relaxed, though I'm unsure of the actual mechanism. Vitamin d is not the problem since I take plenty of it in the form of supplements and fatty fish. Recently I discovered that blue light can help break down bilirubin in the blood, and since I have Gilbert's syndrome, that might be one explanation.
According to this article, Vitamin D supplementation is showing not to “work,” and the theory is that the correlation with health is actually as a marker for UVB exposure. If your black light is putting out UVB then maybe that’s what’s helping you?
This article gives a short, uncited and unorthodox summary of UVA vs UVB effects. Most chemical effects may be unknown, but a few are well-characterized like pyrimidine dimer related mutations from UVB that are also seen in skin cancer sequencing samples. UVB has therefore been thought to be directly carcinogenic (likely indirectly as well through other mechanisms), whereas UVA is often associated with photo aging (longer wavelength, penetrates deeper through epidermis into dermis leading to solar elastosis) and may have carcinogenic role that is less chemically obvious compared to the dimers.
A quick search on Amazon reveals UVB lamps are mainly either expensive ($250) and for people with skin problems, or else cheap and low-powered ($30) for reptiles.
There doesn't seem to be anything for a kind of full-body health use?
