January 21, 2020

Is Melatonin Right for You?

If you or a loved one are affected by restless legs syndrome (RLS), then you likely suffer from disrupted sleep. In fact, a person with moderate to severe RLS averages less than five hours of sleep per night, according to experts. Sleep deprivation is linked to many negative health effects, including depression, which can have a profound impact on a person’s day-to-day life.* Therefore, it makes sense to seek an intervention that may improve quality of life.

Many people who have difficulty sleeping turn to an over-the-counter supplement: melatonin. Melatonin is a naturally occurring hormone that is produced by the pineal gland in the brain to regulate the circadian rhythm, or the body’s internal clock. The release of melatonin is controlled by light. As daylight fades, usually one to three hours before bedtime, melatonin levels increase, which helps promote sleep. In the morning, the increase in daylight signals to the brain to halt melatonin production, aiding the transition to wakefulness.

More than 3 million adults take melatonin as a sleep aid, according to the National Center for Health Statistics. However, the effects of melatonin seem to vary; its effectiveness largely depends on the dose and timing of the supplement, as well as the sleep disorder being addressed.

Research on circadian rhythm sleep-wake disorders sheds light on the use of melatonin to improve sleep. According to the clinical guideline for treating these disorders (Auger, et al., 2015), studies have shown mixed results when administering melatonin to people whose circadian rhythm sleep-wake disorders stem from external alterations to their sleep cycles, such as shift work or jet lag. In one study, melatonin improved the length and quality of daytime sleep for people with shift work disorder in some, but not all participants. In another study of people with jet lag disorder, melatonin was more effective than the placebo for the first three days after traveling, but then lost its advantage. For circadian rhythm sleep-wake disorders that fall under the category of internal alterations in the timing of sleep, such as irregular sleep-wake rhythm, current data does not support the use of melatonin as a treatment. This may be relevant to RLS, since RLS follows a circadian pattern – that is, with most intense symptoms in the evening and nighttime hours. More research with a greater number of participants is necessary to determine the usefulness of melatonin across the board.

Nevertheless, melatonin may help one’s sleep schedule if taken at the right time and at the right dose. Typical doses of melatonin range from 0.5 mg to 5 mg. Higher doses should be avoided, even though there are many over-the-counter products available in doses as high as 10 mg. The best timing for most people is one to three hours before bedtime. It makes sense to consider melatonin as a potential option for a good night’s rest – but not necessarily for individuals with RLS; melatonin has been shown to trigger symptoms of RLS for some people. In a small study, researchers found a significant increase of sensory and motor symptoms of RLS when participants took melatonin compared to those who did not (Whittom, et al., 2010). Why is this?

Although RLS follows a circadian pattern, RLS is believed to be a sensorimotor disorder of the central nervous system. Research has shown that brain iron deficiency contributes to RLS, particularly within brain cells that contain the neurotransmitter dopamine. In terms of the sleep-wake cycle, dopamine is associated with wakefulness because it hinders the neurotransmitter norepinephrine, which then blocks melatonin release from the pineal gland. Because the human body operates under a system of checks and balances, melatonin also hinders release of dopamine in the central nervous system, thus creating a feedback loop. Since melatonin contributes to lower levels of dopamine, and lower levels of dopamine are associated with worsening RLS symptoms, some scientists suggest that melatonin may play a role in exacerbating RLS symptoms.

Another characteristic to note is that melatonin is serotonergic, which means that it is made from the same starting molecule (or building block) as serotonin – a neurotransmitter produced by the body that contributes to feelings of well-being and happiness. While serotonin’s role in regulating the sleep-wake cycle is complex, studies show that increases in serotonin reduce rapid eye movement sleep (REM sleep, the stage in sleep generally associated with dreaming) and can aggravate periodic leg movements of sleep. This is consistent with the fact that a common class of antidepressant medications that increase serotonin called selective serotonin reuptake inhibitors, or SSRIs, cause a worsening of RLS symptoms.

The bottom line is that melatonin may or may not help individuals sleep depending on many different factors. For people with RLS, it is important to know that taking melatonin comes at a risk of potentially aggravating symptoms. As always, you should to talk to your doctor before starting or stopping any treatment, even when they are marketed as naturally produced supplements.

*See Depression and RLS, available in the member portal at www.rls.org or by request.