Hi Beth, not sure what ON headaches are.
Melatonin is vary hard to assess for effectiveness, as so many other variables come into play.
Apparently you need to wait until you are sleepy before taking it.
I still think I feel better the next day though, if I've taken it.
My headaches can be from nerve irritation, principally Occipital neuralgia, or muscle soreness from the one that goes down the neck and into the shoulder. Muscle relaxants are good for this, plus a pain med.
I also take Super Curcumin, B12, multi vits, calcium, SAMe, fish oil.
Something in there must help!!!