John,
 
GNC used to carry liquid melatonin.  But I believe they have stopped
making it, because I can't seem to find it anywhere.  So I started
getting Melatonin Liquid at my local natural market by Natrol, Inc.
You can go to: http://www.natrol.com/products/index.htm and search for
"melatonin" (the liquid is SKU# 457) and at the top of the page there is
a "where to buy" link.  Enter your zip code and it will tell you where
you can purchase it.
 
I hope this helps!
 
Leslie
[Posted in FML issue 5173]