Forgot to add, Melatonin is not recommended if you have POTS. At least it's listed on the DINET.org site, but I'm still taking it. I can't really sleep without it. Sometimes it makes me a little light headed but I'm usually in bed by that point. And I did 1-1/2 years of nightly immovane/zopiclone and it did the same thing, except much worse, and I would be really groggy/non-functioning the next day. I don't notice that with the melatonin. But everyone is different.