Dear Doctor: Melatonin gets mentioned a lot when people talk about the problems they have with getting to sleep. I’ve been thinking about trying it to help me stay asleep, but I’m not really sure that I understand it. What is melatonin, and how does it work?
Dear Reader: Getting adequate and high-quality sleep was already a challenge before the pandemic. These days, a good night’s sleep has become even more elusive. Stress, anxiety and a decrease in physical activity all play a role. So can the amount of time we spend indoors, which separates us from the changing light cues our bodies use for sleep regulation. Rather than prescription sleep aids, many people are seeking out nonmedical solutions. Among these is melatonin. It has been part of the can’t-sleep conversation for so long, and is so widely available, it’s easy to be aware of it without knowing what it is.
Melatonin is a hormone produced by the pineal gland, which is located in the middle of the brain. It processes information about cycles of light and dark in the environment and plays an important role in the timing of our body’s circadian rhythms, which are the 24-hour cycles of our internal clocks. As daylight fades and night arrives, the shift from light to dark triggers the pineal gland to begin to secrete melatonin. It’s released into an area of the brain known as the third ventricle, and from there it enters the circulatory system. Secretion of the hormone begins soon after sundown, peaks at about 2 or 3 a.m., and then gradually decreases. The decline of melatonin levels toward the end of the sleep cycle helps with awakening.
Melatonin itself doesn’t actually cause sleep. Rather, it affects the complex array of metabolic processes that set the stage for sleep. Melatonin receptors have been found in virtually every part of the body, including the skin, kidneys, lungs, liver, breasts, gall bladder and small intestine.
Although we mainly think about melatonin in relation to sleep, it’s fascinating to note the hormone has a wide scope. It’s involved in the regulation of blood pressure and body temperature, distribution of the blood supply, immune response, antioxidant activity, body mass, bone density, sexual maturity and reproduction. However, the specifics of its roles outside of the sleep-wake cycle are not yet fully understood.
With our use of artificial light to extend day into night, we alter the pineal gland’s cycle of melatonin production and release. This has led to the popularity of melatonin supplements. Research shows that it is safe for short-term use and may be useful for those who struggle to fall and stay asleep. It can also help with the effects of jet lag.
Start with a small dose, about .05 milligrams, taken two to three hours before bed. Potential side effects can include headache, nausea, dizziness and grogginess. People with major health conditions such as liver or kidney failure, or women who are pregnant, should seek medical guidance before trying it. And don’t forget about the importance of limiting bright light a few hours before bed, particularly the blue light that emits from computer, tablet and smartphone screens.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA 90025. Owing to the volume of mail, personal replies cannot be provided.)
