> The science is relatively clear on light though. AFIK since is clear on: - a increase in blue intensity reducing melatonin production - higher melatonin le

> The science is relatively clear on light though. AFIK since is clear on: - a increase in blue intensity reducing melatonin production - higher melatonin levels before sleep helping with falling asleep - melatonin is an important factor when it comes to the regulation of the inner clock but the exact degree to which led light will make it harder to sleep, especially if in combination with other sleep issues, is much less clear cut For example melatonin doesn't make you sleep, it (simplified) puts your body in a state in which it's easier to fall asleep. While that might sound like it's the same on the first look it's quite a huge difference. In a certain way you could say melatonin is a major way our body signals itself "now is a good time to sleep", making it somewhat easier to fall asleep. But people do not need melatonin to fall asleep. Some people can (oversimplified) fall asleep whenever they want, some are conditioned to fall asleep under some specific trigger. In both cases this often works pretty much unrelated to melatonin. In the other direction if you have some issues which bare you from sleeping, e.g. bouts of anxiety or somniphobia, then having more or less melatonin is unlikely to make it difference, you won't sleep either way (EDIT: until you are strongly sleep deprived, overcome the anxiety or take some sleeping pills). Anyway reducing the intensity of light in the evening, especially blue light, and making sure you get a lot of light in the morning (i.e. sun light, because your indoor light bulbs are most likely much much less intense) is always a good idea, even if it (hypothetically) would not affect melatonin it still would help with creating healthy habits, and habits are powerful.