Any evidence for the efficacy of 5-HTP?

I tend to frown on people just going to Skeptic for their information gathering on things, so it's with a bit of shame that I come to ask you if anyone has thoughts on 5-HTP, if it actually does any of what it says, and whether there are any health issues related to it.

I tried searching all the various skeptical sources and even looked at a few papers on Google Scholar, but I didn't find anything I felt was concrete and definitely nothing looking at it from a skeptical viewpoint.

Is there anyone with better search skills or a longer memory that could point me in the right direction or tell me what they remember about this particular supplement?

Thanks for any help.