Controlled studies, shows that it does work in test subjects. The ISTM (International Society of Travel Medicine) recommendation is the 3-5 mg as I said above, this also correctly corresponds with research that was just presented from a group in Zurich. As with other medications, sensization can occur, hence the need to adjust dose. And lastly, too much melatonin will prolong "night" as endogenous melatonin rises during the bedtime hours, peaks out in the early morning, and drops back to daytime levels there after. So too much or too little, doesn't cause a proper phase shift to obtain what the melatonin level would be in that of a person who resides in the "new" time-zone. It's interesting that blind people have this "free running" melatonin profile, since they are unable to know the differnece between night and day.