Why use f.lux when you can just pop a metatonin pill thirty minutes before sleep? I've been doing that and I sleep like a baby every night regardless of how long I stare at my bright monitor beforehand.
I imagine melatonin works better with minimal exposure to blue light after taking it. This might be good for those who have it harder time with sleep schedules than you do.
Like any other bright light source (such as the Sun), the light coming from the monitor breaks down some of the melatonin that your body naturally produces. You may still become tired when using a computer and subsequently fall asleep, but the quality of that sleep will be adversely affected unless you account for reduced melatonin levels somehow (either via a program like f.lux, or with supplemental pills).
Melatonin is prescription only in the UK. So, go careful if you're travelling from US to UK with off the shelf sleep meds.
I read some article that investigated melatonin supplements in the US. It said that because supplements aren't as heavily regulated you couldn't be certain which pills had melatonin or how much.
I imagine melatonin works better with minimal exposure to blue light after taking it. This might be good for those who have it harder time with sleep schedules than you do.