I've had a long struggle with sleep. The most effective supplements are:
* magnesium (threonate form before bed)
* D3 BUT MUST BE TAKEN WITH magnesium. 5000IU + 500mg magnesium. These two are linked. Taking D3 without magnesium can make a magnesium deficiency worse. This made a monumental difference for me.
* B complex also very important
* Glycine improved my quality of sleep