Interesting. I work on call shifts. (Linux sysadmin, one week out of three is 24/7 on call -- which works much better than rotating one day out of three.) I've used Melatonin for years to 'regulate' my sleep cycle so that I can stop my tirelessly creative brain from thinking about that article I read a few hours ago on Hacker News. My other 'hacks' to keep my sleep cycle regulated are f.lux where possible, using only…
Melatonin does NOT work as a remedy for jet lag. I don't find open access links to the relevant studies right now but http://www.nojetlag.com/melatonin.html might give you a first idea.
I take 1mg of melatonin between 7 and 9pm in the target time zone's frame, usually starting the day I travel or sometimes the day before. This translates to taking a pill at noon or so in SF before flying to Europe. I follow that up with a pill on the first few evenings of a trip.
I've been doing this for a few years now, and the only remnant of jetlag on such trips is that I feel terrible around 3pm in Europe, which translates to 6am. So I'm guessing that my natural not-yet-shifted sleep cycle is rebelling at that point and trying to convince my body that I just stayed up all night.
Of course, I am an n=1 population size, and the routine has worked so well that I haven't dared to do a significant time zone shift without it. So it could just be me, or it could be the placebo effect. And I'm perfectly ok with that, as long as the jet lag stays at bay.