CLIP >>>http://ods.od.nih.gov/factsheets/list-all/Melatonin/
Main Results:

Effectiveness of Exogenous Melatonin: People with a Primary Sleep Disorder: Melatonin decreased sleep onset latency; it was decreased greatly in people with delayed sleep phase syndrome and marginally in patients with insomnia. There was no evidence that melatonin had an effect on sleep efficiency. The magnitude of the effect of melatonin on sleep onset latency in people with delayed sleep phase syndrome, but not in people suffering from insomnia, appears to be clinically significant. People with a Secondary Sleep Disorder: There was no evidence that melatonin had an effect on sleep onset latency, but it increased sleep efficiency. The magnitude of the effect of melatonin on sleep efficiency in people with secondary sleep disorders appears to be clinically insignificant. People Suffering from Sleep Restriction: There was no evidence that melatonin had an effect on sleep onset latency or sleep efficiency. Safety of Exogenous Melatonin: There was no evidence of adverse effects of melatonin with short-term use.


Main Conclusions:

Evidence suggests that melatonin is not effective in treating most primary sleep disorders with short-term use, although there is some evidence to suggest that melatonin is effective in treating delayed sleep phase syndrome with short-term use. Evidence suggests that melatonin is not effective in treating most secondary sleep disorders with short-term use. No evidence suggests that melatonin is effective in alleviating the sleep disturbance aspect of jet lag and shift-work disorder. Evidence suggests that melatonin is safe with short-term use.

>>http://ods.od.nih.gov/factsheets/list-all/Melatonin/

It is Not Effective in treating most primary sleep disorders???

I'll stick to what WORKS for me, I appreciate your concern.