Here is a partial list of what one company promises sitting under a small panel of red lights will improve: athletic performance and recovery (owing to faster muscle recovery and joint repair), sleep (thanks to increased melatonin production and a “healthy circadian rhythm”), and skin quality (because of reduced inflammation and increased collagen production).

These red lights, in this case made by Joovv, are one of dozens of at-home versions of what’s known as light therapy, or photomedicine, or photobiomodulation, a technology based on the idea that light can change us on a cellular level. This past summer, the journal Frontiers in Medicine published an issue dedicated to photomedicine, and its 12 articles have an overwhelming effect similar to Joovv’s marketing copy, covering dermatological concerns like aging, skin cancer, and psoriasis as well as autoimmune diseases like type 1 diabetes. I like the way a 2016 journal article phrases it with a bad joke that gives away the researcher’s quiet exuberance: After a brief overview of peer-reviewed light-therapy treatments (for arthritis, hearing loss, and chemotherapy side effects), the conclusion states that “after decades confined to the ‘scientific wasteland,’ [photobiomodulation] may be finally emerging into the light of day (pun intended).”

It's pretty amazing what you can do with light these days, with narrow spectrum LEDs that can only produce the light you want.