Since the big criticism of this article was lack of proof of safety, which is a negative and rather hard to prove (who's going to pay for a long-term study of safety when there are lots of reasons to think there is no problem and bigger fish to fry?), I've given a try of the opposite - showing that melatonin supplementation improves health; see the last paragraph of http://www.gwern.net/Melatonin#use

If our computer use is massively cutting our melatonin secretion and lack of melatonin causes noticeable health problems in the most studied group (shift workers), then it seems straightforward to me that supplementation back to the baseline will improve health.

(Quickly looking, none of my refs give specific total secretion amounts, so I can't be sure that taking say 1.5mg exactly counteracts an average 50% fall, but it doesn't seem likely that 1.5mg or 3mg will overshoot by a grotesque & harmful amount.)