My experience:

For about the last 5 years, I have been taking 2 of the small (3mg or 5 mg?) tablets about 30 minutes before going to bed at my destination (after trans-Pacific or trans-Atlantic flights). I continue this for the first 5 days after arrival (including day of arrival).

I have found this helps me sleep through the night, instead of waking up at 2 AM and staring at the ceiling. In short, seems to work for me.

Although perhaps it's just the placebo effect. I am awfully gullible.