Zinc, Vitamin B Complex
I went through a terrible period of insomnia that lasted over 2 years. During that time I was taking Vitamin D3 and Vitamin K2 which I had taken for many years for other medical conditions. I tried numerous additional vitamins and supplements in addition to the two I've mentioned above to help with the insomnia but nothing helped. I wasn't falling asleep until between 5am and 8am most nights and then would wake again after a few hours. I felt mentally and physically broken.
Nine months ago I started taking Zinc Picolinate 30 mg one a day and Vitamin B Complex capsules 82 mg one a day. From the very first day, my sleeping went back to normal and has stayed normal to this day. I just make sure I take them religiously, usually early evening.
Hope this might be of some help to you.