Melatonin is a hormone that naturally occurs in our bodies and helps maintain our sleeping patterns. It is available for purchase as an over-the-counter sleep aid, and is also used to combat jet lag. The University of Maryland Medical Center (UMMC) explains that melatonin supplements can help people who have a disrupted sleep-and-wake cycles such as those who work night shifts, the elderly and schizophrenic patients. Melatonin is a medication and you should discuss taking it with your doctor prior to starting treatment.
Change in Dreams
Melatonin may cause a change in dream patterns, or an increase in nightmares. Dreams may also become much more vivid while taking these supplements.
Change in Sleeping Patterns
Melatonin may cause you to feel sleepy during the day if the dosage is too high. Consult with a doctor regarding an appropriate dosage if this occurs. Melatonin supplements may also throw off your sleeping patterns, causing you to sleep during the day and lie awake at night. Sleepwalking is another possible side effect of this supplement. Additionally, you should use extra caution and not drive or perform tasks that require complete concentration until you understand how melatonin affects you.
Headaches
A headache is the most common side effect of melatonin supplements, explains Drugs.com. Patients may experience migraine headaches as well. If these side effects persist, consult with your doctor for an alternate therapy or for treatment advice for the headaches.
Stomach Upset and Mood Disturbance
Melatonin may cause abdominal cramping in some patients, as well as irritability and dizziness. Additionally, melatonin may cause decreased libido. The UMMC also notes that melatonin may increase depression symptoms in some patients.
Fertility
If you are trying to conceive, do not take melatonin. According to the UMMC, melatonin may cause decreased sperm counts. Also avoid this supplement if you are pregnant or nursing.



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