I've been using melatonin for years now. I recommended it as part of my health article a while back.

When I started I was careful to always take a <1mg dose. More recently (due to laziness really) I have just been taking whatever dose I found at the store without bothering to break the tablets apart.

Your article reminded me that the current 3mg tabs I have are probably too much. This dose still works fine for me, but I have noticed a higher incidence of headaches which could be connected.

PS, good work on your site gwern, I find your research useful.