I read about using 1/8 - 1/4 teaspoon of borax in water for various health issues, although not insomnia specifically. I decided to try it, and right away noticed that I was able to fall asleep easily and sleep through the night better. I've had insomnia & nightmares for years & have tried many natural supplements & remedies. I'm often tired but don't feel sleepy...after so many years of insomnia, I LOVE that delicious sleepy feeling! Magnesium has worked ok for me but gets expensive & sometimes I'd be awake for an hour or more after sleeping for just a few minutes. Perhaps the borax is detoxifying flouride or something from my body, or killing off a fungus that was affecting my health. However, I've skipped the borax twice in the last few weeks and had a horrible time that same night. I've read that boron helps you absorb calcium better, and calcium helps you relax and sleep, so maybe that's why it's helping me. In the morning I prepare a liter bottle with 1/4 teaspoon borax and sip it throughout the day. Even if I finish it in the early afternoon or drink the whole bottle an hour before bed, it seems to work.
EC: More about borax here.