Dunno about the US, but in Norway there a prescription version that's 2mg total in an extended release formulation. It's a fairly optimal dosage repeated throughout the night. It's technically meant for elderly people who can't stay asleep very well, but it's been pretty easy to get it off-label(doctors will basically be thrilled to be "drug-seeked" for just melatonin instead of benzos or Z-drugs for once, IME), and the price is reasonable, especially now there's a generic version.

Did absolute wonders for my overall sleep quality anyway. And I struggle with both insomnia and frequent awakenings.