The safety of melatonin, a commonly used over-the-counter sleep aid, is under question in a new investigation by the American Academy of Sleep Medicine.
Although packaged like a supplement, melatonin is a hormone. It's released by the brain's pineal gland. Levels increase when the sun goes down to induce sleep and then fall again when the sun rises to induce wakefulness.
The academy's current recommendation while the investigation is underway is for adults and children to avoid taking the hormone for insomnia. Insomnia, by definition, is disrupted sleep at least 3 times a week for more than 3 months that leads to daytime sleepiness.
Why this recommendation? The academy needs more information on melatonin's effects on other body systems. Melatonin also affects body temperature, blood sugar and blood vessel tone.
Melatonin was recently the subject of a study looking at doses and impurities in over-the-counter products. The study found discrepancies between melatonin doses listed on product labels and the actual dose delivered by the product. The study also found impurities in melatonin products, like levels of another chemical messenger, serotonin.
Muhammad Adeel Rishi, MD, vice chair of the Public Safety Committee for the American Academy of Sleep Medicine, warns that serotonin in over-the-counter products when doses aren't known can be especially problematic for people with mood disorders already taking medications. Serotonin also influences the heart, brain and blood vessels.
Rishi states it's important to make sure melatonin products contain a USP verified check mark to know they've met certain standards of the U.S. Pharmacopeia Convention.
Because it is a hormone, researchers are also looking into whether long-term melatonin use delays puberty in children who take it. Researchers think that melatonin in children may affect the onset of puberty by interrupting the decline of natural hormone levels.
Rishi predicts that melatonin will start being regulated as a medication by the FDA.
The American Academy of Sleep Medicine will post results from its investigation on sleepeducation.org in the next few months.
Sources: Medscape, Journal of Clinical Sleep Medicine