Melatonin is a hormone secreted by the pineal gland in the brain to help regulate various body functions, including the sleep cycle. Production of melatonin is stimulated in darkness, and levels of melatonin in the body are highest at night. Increases in melatonin make the body less alert, essentially inducing sleep.
Melatonin supplements are available in most drugstores and pharmacies and are often used as a natural sleep aid for insomnia, jet lag and work shift sleep disorder. Melatonin is generally regarded as safe for short-term use, but patients should be aware of possible negative side effects. If you have a medical condition, are taking any other medications or supplements or experience any side effects, it is best to consult with your doctor before continuing use of melatonin.
Common Side Effects
Common side effects of melatonin include headache, dizziness, nausea, irritability and stomach cramps.
Melatonin may cause daytime drowsiness. This can often be remedied by taking a lower dose of melatonin, but patients who must drive or operate heavy machinery should use caution.
Some patients experience vivid dreams or nightmares while taking melatonin, and dreams may be remembered more frequently. Melatonin may also cause sleepwalking. These symptoms typically subside after discontinuing the melatonin.
Incorrect or overuse of melatonin may disrupt the circadian rhythm, resulting in irregular sleep-wake cycles.
Melatonin may cause changes in levels of hormones such as progesterone and luteinizing hormone. Pregnant or nursing women, or women trying to become pregnant, should not take melatonin. Excessive melatonin use may even have a contraceptive effect, and high levels of melatonin during pregnancy may cause developmental disorders.
In men, melatonin may also increase breast size (gynecomastia), decrease sperm count and decrease sperm motility. Decreased sex drive has also been reported in both men and women.
Melatonin may cause mood changes such as giddiness or sadness and worsen pre-existing symptoms of depression. In some cases, psychotic symptoms such as delusions, hallucinations and paranoia have been reported. Therefore, individuals with depression or psychotic disorders should consult with their doctor before taking melatonin.
Blood and Cholesterol
Melatonin may decrease blood pressure and increase cholesterol, as well as elevate blood sugar levels in patients with Type 1 diabetes.
Melatonin may interact with a number of common medications, including antidepressant and antipsychotic medications, non-steroidal anti-inflammatory medications (such as ibuprofen), steroidal medications and blood pressure and blood-thinning medications. Melatonin may also interact with commonly used substances such as alcohol, caffeine and tobacco.