UV light-on-skin exposure catalyzes Vitamin D synthesis in the skin, which has a myriad of positive biological effects, including, but not limited to, likely helping fight disease, reduce depression, boost weight loss, promote calcium absorption and bone mineralization, and reduce inflammation. The D-Light is the first ever consumer product made with UVB LEDs, the specific portion of the UV spectrum that leads to Vitamin D synthesis.
Full Spectrum Sky Portal
The sun is extremely bright on the surface of the Earth, even during a cloudy day. Your brain uses that intensity of light as it's main indicator that it is daytime, eg. that it is time to be awake and alert. So, what happens when you live indoors, and the amount of light that is entering your eyes is, on average, 100x less than what enters your eyes during even a cloudy day? We have our hypotheses, but needless to say, it's not good.
Some of the main effects people are interested in with Near-Infrared light are cognitive and sleep enhancements, better looking skin, hypertrophy and faster recovery from physical training, pains/aches, and hair re-growth. Since NIR light works on a mitochondrial level, it is a likely panacea of benefit, considering the prevalence of mitochondria throughout each part of the body.