What is Melatonin?


If you have been struggling with a good night's sleep, you may have been told to use melatonin supplements to help you relax. Before you start supplementing with a hormone, take the time to learn a little more about what melatonin is and what it does. This will help you decide if you need to add additional melatonin to your life.

Melatonin is created by the pineal gland in the brain. In a healthy, normally functioning individual, melatonin is released in a rhythmic cycle, with more melatonin produced at night when the light entering the eyes starts to diminish. The bloodstream carries it to the different areas of the body, where receptors pick up the melatonin to signal the need for sleep.

What does melatonin do?

Melatonin is essential to signaling the relaxation and lower body temperature that help with restful sleep. Levels of melatonin are higher at night, signaling the body that it is time to rest. In animals, the hormone also regulates seasonal biology, such as the reproductive system, winter coat growth, and hibernation behaviors. A connection between melatonin and human reproduction or seasonal cycles has not yet been established.

Because it is so connected to sleep, melatonin has been called the "sleep hormone." However, it is not necessary for sleep, and people can sleep with inadequate levels of melatonin in the body. That said, the secretion of melatonin does allow individuals to sleep better.

Problems Connected with Melatonin

People do not experience problems with melatonin secreted naturally by the body. The amount of melatonin produced by the body, whether low or high, is not associated with any health problems. In fact, in a lifetime, melatonin levels increase and decrease during the various stages of life. Low levels of melatonin do not appear to have any serious effects on health — although it can make sleep difficult to achieve if the levels change.

However, melatonin supplementation as a sleep aid is popular, and sometimes people will take too much melatonin. This can cause drowsiness and a reduced core body temperature. Extremely high levels of melatonin can also contribute to headaches and fatigue. It's also possible for very large doses of melatonin to affect human reproduction.

Questions to ask your doctor

If you are considering taking melatonin supplements to help with sleep, talk to your doctor first. Ask:

  • How much melatonin do I need?
  • How much melatonin is too much?
  • How long can I take melatonin safely?
  • Is long-term melatonin use dangerous?
Last Updated:

About this Content

The Hormone Health Network is the public education affiliate of the Endocrine Society dedicated to helping both patients and doctors find information on the prevention, treatment and cure of hormone-related conditions.

Ensuring the Quality of our Content

All Network materials, including the content on this site, are reviewed by experts in the field of endocrinology to ensure the most balanced, accurate, and relevant information available. The information on this site and Network publications do not replace the advice of a trained healthcare provider.

Advertisements and Site Content

Paid advertisements appear on the Hormone Health Network. Advertising participation does not influence editorial decisions or content.

Back to top