jet-lag - melatonin can help
Melatonin used to be prescription in Australia, but is now available as homeopathic medicine, since the tablets are only 3mg.
I have found Melatonin useful for jet lag (not for regular use) - I take 4 tablets, as one seems to have little effect, and I only take it when I am not already sleepy - like if I am wide awake at 2am and need to sleep.
I rarely get more than 4 hours sleep from the use of Melatonin tablets, but that can make the difference when fronting up to a client the next morning!!