Melatonin IR/XR contains 1.5 mg of MicroActive Melatonin. an innovative 50/50 blend of immediate- and extended-release melatonin to help you fall asleep quickly and stay asleep all night long. A lack of quality. restful sleep can affect cognitive health. metabolic health and more. Poor sleep can mean that you have trouble falling asleep. but it can also mean that you wake up in the middle of the night and can't get back to sleep. Melatonin IR/XR is the perfect sleep support supplement for those who have already tried melatonin but still had trouble getting to sleep or staying asleep.