05/15/2009 05:12 am ET | Updated Nov 17, 2011

Melatonin: Miracle or Mistake?

In this day and age, when sleep rhythms can go haywire at the drop of bad news, questions about sleep aids are a hot topic. They are no longer confined to those who are presumed to have oddball sleep cycles, such as jet setters and shift workers.

I get a lot of questions about melatonin in particular, since many supplement companies and health food stores will tout that melatonin is a "natural" sleeping aid. Given the availability of this supplement today, you'd presume it's safe and effective. But is it really?

What's better, taking a melatonin supplement to help you go to sleep on a crazed Monday night or going for a "PM" version of a pain reliever? Melatonin is a hormone your body produces to help it regulate your sleep-wake cycles, but taking additional melatonin in the form of a supplement isn't as good an idea as you might think.

  • It's not a regulated drug under the FDA.
  • No other hormone is available in the United States without a prescription.
  • In Europe, melatonin is only available by prescription.

So here's the 101 on how natural melatonin -- the kind produced by your body -- works. When the sun sets and darkness sweeps over, a pea-sized structure located deep between the hemispheres of your brain called the pineal gland begins to secrete this hormone, preparing you for bed.


As melatonin levels in the blood rise, you begin to feel less alert and sleep becomes more inviting. Melatonin levels stay elevated for about 12 hours, falling back to low daytime levels by about 9 a.m. Daytime levels of melatonin are barely detectable.

The precise mechanism of melatonin secretion is not well-known. We do know, however, that melatonin isn't just about sleep-wake cycles.

  • It's been shown to help regulate the female reproductive cycle and may also control the onset of puberty.
  • Children who take melatonin can suffer a delay in sexual development. (So never ever give a child a melatonin supplement.)
  • Studies have pointed to melatonin's role in regulating blood flow, specifically in constricting coronary arteries.
  • It's been suggested that it can increase depression in people prone to the illness.

A hormone with all of these possible effects -- even though it's "natural" -- isn't something you should be taking without the specific recommendation of your doctor.

Most commercial products are offered at dosages that cause melatonin levels in the blood to rise to much higher levels than are naturally produced in the body. So taking a typical dose (1 to 3 mg) may elevate your blood melatonin levels to 1 to 20 times its normal state. If you take it at the wrong time of day, you may reset your biological clock in an undesirable direction.

How much to take, when to take it, and melatonin's effectiveness, if any, for particular sleep disorders is only beginning to be understood. Remember, melatonin is a sleep regulator, not a sleep inducer, so it really should not be used as a sleeping pill. In the future, we may find several useful applications of melatonin.

You're better off regulating your own sleep-wake cycles in a genuinely natural way by:

  • exposing yourself to light during the day (preferably sunlight),
  • engaging in physical activity regularly,
  • practicing good sleep hygiene.

Remember: Your body will reset its own internal clock with the proper exposure to light at the right time. (And you shouldn't need a PM formula, either, unless you truly do need an occasional fix for quelling muscle aches or other pains that can prevent you from going to sleep easily. Just don't make this a habit every night.)

Bottom line: better sleep hygiene, better time going to sleep. And better moods the next day. Melatonin, on its own, is not a sleeping pill.

Sweet Dreams,

Michael J. Breus, PhD, FAASM

The Sleep Doctor

This sleep article is also available at Dr. Breus's official blog, The Insomnia Blog.