Doxylamine
"I've suffered with insomnia for many years & have tried various remedies including Yoga based approaches & treatments using natural products like Valerian. Unfortunately, none of these has had any lasting effect. 

Usually, I will manage to get to sleep but will wake up three or four hours later & then have a real struggle to get back to sleep no matter how relaxed I am. Consequently, I'm absolutely shattered the next day and find it very hard to function properly. With Doxylamine, however, I usually enjoy a good night's sleep (6 to 7 hours) and feel energised the next day. I've been taking them for over three years now and don't appear to have any side effects. I take about half a tablet each night and drift of to sleep about an hour later"