Melatonin is the least toxic substance… or at least that’s what /they/ say. Since supposedly higher doses give you higher probability of lucidity, I will try it.
How much would I sleep if I did such thing? >_>
Interesting… melatonin is beginning to appear in other local pharmacies now… I just bought 3mg melatonin tablets today…
It is sayed that 6 mg are more than sufficiant if you don’t want to treat insomnia
here it is a pharmacy-only substance , meaning you can’t buy it at the supermarket … 
I used melatonin some years ago , it gives long dreams , and obviously helps if you are insomniac , but the best thing is : you can do awesome WBTB with it ,