Melatonin
Sleep is often on our minds, and we can frequently find ourselves looking for ways to improve our sleep. Recently melatonin has thrown its hat into the ring as a way to get people sleeping better. This article looks at melatonin and explores its role in improving sleep.
Melatonin is a natural hormone produced by the brain. Why melatonin is relevant to sleep comes back to the key systems for controlling sleep, one of which is the circadian rhythm.
The circadian rhythm is also known as the internal body clock. It has evolved because as humans, we need our bodies to behave differently at different times of the day. For example, as humans, we are very reliant on light to carry out our activities and so we have evolved to be more active during daylight hours and sleep at night. This pattern of behaviour continues with its own internal momentum. There are many body processes that work in line with the circadian rhythm, but the control of sleep and wake is probably the most well-known.
There are different hormones associated with the wake-phase and sleep-phase of the circadian rhythm, and it is through these hormones that our various body functions are controlled.
During the wake phase, the dominant hormone is cortisol, which helps our body carry out many of its ‘wake’ functions, and during sleep, the main hormone is melatonin.
Melatonin signals to your body that it is entering the sleep phase and that it should get ready for this.
Melatonin is produced by a part of the brain called the pineal gland and is released into the blood where it can work all over the body.
Melatonin influences other body processes, such as reducing your body temperature and lowering your blood pressure. There is also research suggesting that melatonin also improves the ability of your immune system to fight off infections, and through its work as an antioxidant, it can reduce the rate at which your body ages.
The melatonin level is almost undetectable during the day but suddenly peaks around 2 hours before your normal bedtime, as you get ready to move into the sleep phase of your circadian rhythm.
What is melatonin?
What influences melatonin production?
Melatonin is the hormone for night time, and as such, is influence by levels of light. Bright light, which you would normally associate with daytime, inhibits melatonin production. There are other activities you can do during the day that influence melatonin production, such as exercise.
Melatonin production also changes over your lifetime. Production begins in childhood and peaks as a young adult, the then drops in middle ages and can be extremely low in older adults.
Melatonin itself is made from an amino acid called tryptophan. Your body can’t make tryptophan - its known as an essential amino acid, and so must comes from your diet. Foods that are rich in tryptophan include turkey, and certain types of cherries.
Will melatonin help me sleep?
It certainly makes sense to think that if melatonin is the hormone of sleep, then taking melatonin will improve this. However, the answer of whether it will help you sleep or not isn’t so straightforward.
Firstly, melatonin relates to only one of the two systems of controlling sleep (the circadian rhythm), so just altering melatonin levels is only part of the story.
Secondly, melatonin is responsible for signalling to the body that it is entering the sleep phase, rather than for causing sleep itself.
The way this signal is given is through the sudden production of melatonin – and we know that this is influenced primarily by light, but also daytime activity.
Difficulties in making a clear transition from the wake phase to the sleep phase of your circadian rhythm are less due to an overall deficiency in melatonin, but more due to the uncoordinated exposure to the stimuli that trigger its production – namely light, exercise, and also through having an inconsistent waking and sleep time.
This is why taking extra melatonin has only been shown to help sleep in certain situations.
What makes a bigger impact is properly coordinating the stimuli that influence its production.
However, there are a few exceptions, and these relate to the population groups that produce less melatonin – children, and older adults.
Who benefits from melatonin supplements?
The big research studies have shown that when your body doesn’t produce much melatonin, melatonin tablets can help.
Research has also shown that in the over 55-year-old group, there are improvements in sleep that can be experienced with melatonin.
There is another group of people shown to benefit from melatonin tablets, and these are people suffering from jet lag.
Jet lag is a type of circadian rhythm disorder where, because of flying across multiple time zones, your body’s internal rhythm is at odds with the local time zone. Your body has a fantastic ability to adjust to a new time zone, but it takes several days to do this – usually one day for every time zone travelled, and during this time you can feel very sleepy and fatigued.
Exposure to the stimuli that influence your circadian rhythm – light and exercise, can help with this adaptation, but evidence has also shown that taking a type of melatonin tablet in a short-acting form can simulate the sudden peak of melatonin that occurs a couple of hours before your usual bedtime, and can bring your circadian rhythm forwards – or backwards – depending on the time that you take it. This should always be done together with coordinated exposure to light and exercise.
Where can I get Melatonin?
In some countries, melatonin can be bought over the counter, but in the UK it is a prescription-only drug.
Studies of melatonin bought over the counter, or from online health shops have shown a huge range in the melatonin they contain. Some tablets contained 247% of the reported dose of melatonin, while others contained none at all.
As melatonin is a drug, we believe it should be made carefully and precisely. The melatonin we prescribe is from official, regulated manufacturers.
How can I sleep better?
In some ways, sleep is a complex process and controlled by many different factors with melatonin being just one of these.
Perfect sleep unfortunately doesn’t exist, but you can often improve it with sleep hygiene is an evidence-based approach to do this. Sleep hygiene is good, general advice for sleep aimed at people who generally sleep ok, or who are only troubled with poor sleep occasionally.
If you sleep problem is chronic insomnia, which is a specific sleep disorder, then sleep hygiene has be shown through research not to be effective.
The best treatment for chronic insomnia is cognitive behavioural therapy for insomnia, or CBTi. Melatonin is also an evidence-based treatment for insomnia in the over 55 years group.
If you would like to discuss insomnia and whether melatonin is the right choice for you, then book a sleep consultation with one of our sleep doctors.
