Thanks for quoting my institution!

I used to take melatonin for jet lag as well, but I have since learned a number of reasons to avoid it.

As you probably know, the US Food and Drug Administration doesn't regulate dietary supplements like melatonin. Unlike prescription drugs, nobody has to prove that the stuff works, that the substance is pure, or that what's in one bottle is the same as the next bottle. The only authority that the FDA has is to pull an unsafe product from the market. There's no "pre-market" approval.

This lack of regulation gained some publicity with the supplement tryptophan. Like melatonin, tryptophan was promoted as a sleep aid. Turns out that a number of trytophan users developed a serious, debilitating, and rare disease called eosonophilia-myalgia syndrome. Researchers discovered that the syndrome was not a result of tryptophan, but a result of a contaminant in the tablets. This SAME CONTAMINANT HAS BEEN FOUND IN MELATONIN.

So melatonin is not only been shown to be ineffective in animal studies, but it's potentally dangerous.

What to do about jet-lag? There are no quick-fix answers. Eating light, getting some exercise, and drinking plenty of water are certainly helpful. There are also a number of new generation hypnotics (Ambien, Sonata, etc.) that some people find useful.

Thought this information might be helpful.