I recently purchased a bottle of Sublingual Melatonin, in the 2.5mg per lozenge dosage. The first night I decided to use it, I was suffering from a moderately sleep-depriving sinus infection. I stuck 2 of the lozenges uner my tongue (orange flavor, muy bien!) and laid down. After approximately 3 minutes, I was feeling EXTREMELY drowsy, at which point I went to bed. I enjoyed very vivid dreams, but upon waking felt slightly 'hung over'.
From the next day onward, I took only one 2.5mg lozenge and have experienced great results. Each night, I can get to sleep when I want (I used to have problems falling asleep, especially on stressful nights-before, like sundays before school) and not feel anything but well-rested in the morning. In addition to feeling better, I have experienced remarkably vivid dreams EVERY night I have taken the 2.5mg dose, and have also had great recall of the dreams. As a smaller note, I have noticed that I feel stronger during the day, not in a muscular sense, but in a 'health' sense, likely supporting the claim that Melatonin is a CNS stimulator and immune system enhancer.
I had a strong hangover and no dream recall when I tried a higher dosage again.