I have to say that I've had no side effects from it at all thus far. I'm doing a lot of fitness training right now, and i think the 5HTP is part of what's helping my motivation. It's also prevented me from having any really immobilizing depressions. Sometimes I feel a little down, but can perspectivise, pick myself up and focus on uplifting things.
So, improved mood (socialising and planning once more) and I'm fitter than I've been in years.
I wonder why this supplement is not a first line treatment for dep?