I don't know. The jury is still divided as to long term need and efficacy. Some say no problem taking it forever and others say don't do it. I think that a lot is going to depend on dosage. I admit I haven't dug deep in this area though.
It's one of those things I really haven't had a need to form much of an opinion on since I personally can't take it without significant problems.
Other than noting that melatonin comes with baggage and most people take more than is needed...I really haven't thought much about it.
My job is only to provide information...not make decisions.
In general though I still adhere to the "if it ain't broke no need to go fixing it"...kind of thinking.
Not everyone has a problem with unwanted side effects...so if a person doesn't have a problem then there's no need to go trying to fix a problem that doesn't exist....IMHO.
Though if I were a male...the libido side effect would likely scare the hell out of me because I don't think it increases libido. Guys are kinda funny about Mr Woody. Mr Woody is real important to a lot of guys and I guess maybe secondary to a lot of gals as well. All depends on one's perspective I suppose.