Is melatonin a helpful sleep aid — and what should I know about melatonin side effects?

Answer From Brent A. Bauer, M.D.

The hormone melatonin plays a role in the sleep-wake cycle. Natural levels of melatonin in the blood are highest at night. Some research suggests that melatonin supplements might be helpful in treating sleep disorders, such as delayed sleep phase. They also may provide some relief from insomnia and jet lag.

Melatonin is generally safe for short-term use. Unlike with many sleep medications, with melatonin you are unlikely to become dependent on it, have less response to it after repeated use or experience a hangover effect.

The most common melatonin side effects include:

  • Headache
  • Dizziness
  • Nausea
  • Daytime drowsiness

Other, less common melatonin side effects might include:

  • Vivid dreams or nightmares
  • Short-term feelings of depression
  • Irritability
  • Stomach cramps
  • Diarrhea
  • Constipation
  • Decreased appetite
  • Urinary incontinence at night
  • Increased risk of falls
  • Increased risk of seizures
  • Confusion or disorientation
  • Mood swings
  • Reduced alertness

Because melatonin can cause drowsiness, don't drive or use machinery within five hours of taking it.

Melatonin supplements can interact with some types of medicine, including:

  • Medicine that slows blood clotting
  • Medicine that prevents seizures
  • Birth control medicine
  • High blood pressure medicine
  • Diabetes medicine
  • Medicine that suppresses the immune system (immunosuppressants)
  • Medicine that is broken down by the liver

Before you take melatonin supplements, check with your health care provider first, especially if you have any health conditions or if you are taking other medicine. Melatonin supplements you can buy without a prescription vary widely in the amount of melatonin they contain. Your provider can help you decide if melatonin is right for you and, if so, which one is a good choice for your situation.

And keep in mind that, as with any supplement, melatonin shouldn't be the first or only remedy you use to try to resolve a health concern such as insomnia. It needs to be coupled with lifestyle choices that create a solid foundation for good health. That includes fundamentals such as good nutrition, daily exercise, a daily mind-body practice, good sleep hygiene, social connectedness and spirituality.

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Oct. 28, 2022 See more Expert Answers