Melatonin

Melatonin is a hormone that helps the body keep time. Produced mainly in the brain, melatonin levels naturally rise as darkness falls, signaling that biological night is beginning and helping the body prepare for sleep.

Melatonin plays an important role in regulating the body’s internal clock, also known as the circadian rhythm. It helps coordinate the timing of sleep and other biological processes with the natural day-night cycle.

Melatonin is also widely available as a sleep supplement. It may help people fall asleep or adjust their sleep schedules, particularly when sleep problems are related to the timing of their internal body clock. However, its effectiveness depends on the underlying sleep problem, and taking melatonin at the right time is often as important as the dose.

Melatonin is produced mainly by the pineal gland, a small gland in the brain. Its production is controlled by the body’s central clock, which receives information about light and darkness from the eyes.

As evening light decreases, melatonin levels typically begin to rise about two hours before a person’s usual bedtime. Levels remain elevated during biological night and fall toward morning.

In specialized sleep clinics, melatonin levels can be measured to help determine the timing of a person’s internal body clock. This can be useful when evaluating certain circadian rhythm sleep disorders.

Sleep is regulated by two closely connected processes: the body’s internal clock (circadian rhythm) and sleep pressure, which builds the longer we stay awake.

Melatonin mainly influences the circadian rhythm. Its rise in the evening signals biological night and helps the body prepare for sleep. It can also promote sleepiness when released or taken at the appropriate time.

Sleep pressure works differently. It builds during waking hours, partly through the accumulation of a substance called adenosine in the brain. The longer we stay awake, the stronger the drive to sleep becomes.

Healthy sleep is most likely when the body’s internal clock and sleep pressure are aligned. Melatonin helps regulate sleep timing, but it does not replace the natural need for sleep. Although widely used as a sleep supplement, melatonin is not a cure for insomnia or other underlying causes of disrupted sleep.

Melatonin supplements may help with certain sleep problems, particularly those involving a mismatch between the body’s internal clock and the desired sleep schedule. Their effectiveness depends on the condition being treated and when the supplement is taken.

A healthcare professional may recommend melatonin for:

• Jet lag: To help the body adjust to a new time zone.
• Delayed sleep-wake phase disorder: To help people who naturally fall asleep and wake up much later than desired.
• Non-24-hour sleep-wake rhythm disorder: To help regulate sleep timing, particularly in people who are totally blind.
• Shift work: To help improve sleep in some people who work outside conventional daytime hours.
• Certain childhood sleep problems: In selected cases, particularly when behavioral approaches have not been effective.

Melatonin is generally less effective for chronic insomnia that is not related to circadian timing. Cognitive behavioral therapy for insomnia (CBT-I) is usually recommended as the first-line treatment.

Because the appropriate timing, dose, and formulation depend on the individual and the sleep problem, melatonin supplements should be used with guidance from a qualified healthcare professional.

Melatonin is generally well tolerated when used for short periods, but it can cause side effects, including daytime sleepiness, dizziness, headaches, nausea, and vivid dreams.

Melatonin may also interact with certain medications, and combining it with alcohol or other substances that cause drowsiness can increase impairment.

Pregnant or breastfeeding women, children and adolescents, and people with certain medical conditions should seek medical advice before taking melatonin. Long-term safety remains less certain, particularly in children and with regular high-dose use.

The amount of melatonin in supplements may also differ from what is stated on the label.

• Could melatonin help with my particular sleep problem?
• What dose, timing, and duration would be appropriate for me?
• Is melatonin safe to take with my current medications, or would another treatment be more effective?

Melatonin can be helpful for certain sleep and circadian rhythm problems, but its effectiveness depends on the individual and how it is used.

Melatonin can be useful when there is a clear indication and the timing is correct. It is best understood as one tool for circadian care, not a universal sleeping pill.