My doctor asked me to start taking Melatonin because sleep is the key to creating a good seratonin balance in the brain. He thought that many of my migraines were caused by a lack of seratonin - caused by a lack of good sleep. (seratonin is replenished during the REM cycle I think) I took it for a while and started sleeping much better. The only problem was that eventually my body became used to the vitamin and I started having trouble sleeping again. It did help with my headaches.