What is Melatonin, And What is The Relationship To Restful Sleep?
Melatonin is a natural hormone secreted by the pineal gland. It is primarily responsible for controlling the sleep-wake cycle, signaling the brain that it is time for sleep, making you feel tired, and preparing your body for sleep.
Melatonin's natural blood levels increase during the day and peak at night. Your circadian rhythm (body clock) determines when the peak occurs, so a disrupted body clock can interrupt your sleep-wake cycle.
This article explores the relationship between melatonin and sound sleep, shedding light on the most crucial sleep hormone.
Let’s jump in!
What is melatonin?
Melatonin is a hormone the pineal gland releases to regulate circadian rhythms (the sleep-wake cycle). Circadian rhythms are 24-hour body cycles, running in the background to regulate sleep and wakefulness.
Melatonin release is connected to the time of day. Darkness prompts the release of melatonin, which builds during the day. This is why you feel tired at night—your body is telling you it needs to sleep.
Melatonin also significantly affects sleep quality by facilitating the transition to sleep and helping people fall asleep and stay asleep.
One of the unspoken roles of melatonin is in the immune system – it has immunomodulatory and anti-inflammatory properties, reducing tissue
damage and boosting innate and cellular immunity.
Can you have low melatonin?
Low melatonin levels are possible. However, they are usually not a disorder in themselves but a symptom of other ailments and diseases.
Low melatonin levels are associated with anxiety and depression, observed in people with dementia and type 2 diabetes. Melatonin secretion also decreases as you age due to the deterioration of many circadian rhythms.
If you have low melatonin, this can cause restlessness and sleeplessness. You should speak to your GP if you have concerns.
What are the symptoms of melatonin deficiency?
These are the common symptoms of a melatonin deficiency:
- Restlessness
- Poor stress response
- Insomnia
- Waking up too early and not getting back to sleep
- Weakened immunity
- Anxious thinking at night (cortisol, the stress hormone, suppresses melatonin)
If you have two or more of these symptoms, it is worth speaking to your doctor about low melatonin and getting a blood test.
What can impact melatonin release?
Melatonin release depends on dark and light cycles, with secretion increasing when darkness falls. Bright lights can interrupt melatonin secretion, so it's a good idea to dim the lights an hour before bedtime.
Blue light from devices also suppresses the release of melatonin. If your smartphone has a blue light/night filter, you should turn it on two hours before bedtime. Otherwise, please turn it off and switch it on in the morning.
A disrupted sleep schedule can push melatonin secretion back, making it harder to fall asleep at a reasonable time. Late nights can interrupt your circadian rhythm and make it harder to fall asleep. Please read our guide to fixing your sleep schedule.
Are melatonin supplements a good idea?
Melatonin supplements are not authorised for sale in the UK, so any products you find online are unregulated by health bodies. You can never be sure what is in an unregulated product, so you should swerve well clear of them.
Melatonin can only be purchased on prescription, so you must speak with your GP to see if you can try it as a sleep aid.
Nevertheless, melatonin as a sleep aid is promising. This meta-analysis found that it positively affects sleep quality in adults, as assessed by the Pittsburgh Sleep Quality Index (PSQI). A separate meta-analysis found the same thing.
Some antidepressants also increase/reduce melatonin secretion as a side effect – refer to your medicine’s literature to find out more.