Melatonin is a natural hormone that has been hailed as a wonder drug, able to cure everything from insomnia and jet lag to improving sex drive, slowing ageing and even protecting against cancer.
Synthetic melatonin, which is identical to the natural hormone, is freely available as a food supplement in some countries such as the US. In the UK, however, melatonin was classified as a medicine in 1995, and over-the-counter sales banned. Melatonin is only currently available in the UK as the prescription drug, Circadin, to treat insomnia with poor quality sleep in patients aged 55 or over, as melatonin production is known to decrease with age. However, it is not illegal to import melatonin hormone products for your own use from countries where it is freely on sale. But is it wise to do so?
What is melatonin?
Melatonin is your natural sleep hormone that’s produced in the pineal gland of the brain at night. Its production is regulated by exposure to light, and naturally peaks around 2 am, when melatonin concentrations within the brain are between 10 to 100 times higher than during the day.
Melatonin interacts with brain receptors (MT1, MT2 and MT3) to regulate your internal body clock and circadian rhythm to promote sleep. Melatonin also appears to lower body temperature and makes you feel sleepy in a similar way to animals that hibernate.
Melatonin for sleep
In its prescription form, melatonin is used at a dose of 2mg once a day, 1 to 2 hours before bedtime, and after food. It is licensed for the short-term treatment of primary insomnia characterised by poor quality of sleep in patients who are aged 55 or over, and can be continued for up to 13 weeks.
In clinical trials involving people with insomnia, taking 2 mg melatonin every evening for 3 weeks improve sleep latency (time between going to bed and falling asleep) and improved subjective feelings relating to quality of sleep, refreshing sleep and daytime functioning (restorative sleep) with no effect on concentration or vigilance, and no hang-over effect the day after.
Sleep studies with brain wave recording (polysomnography) showed that taking melatonin helped people fall asleep between 9 minutes and 11.4 minutes more quickly than with placebo. There were no changes in the structure of sleep (pattern of light and deep sleep phases) and no effect on the duration of REM (rapid eye movement or dream) sleep.
Overall, 47% of people using melatonin tablets experienced significant improvement in both quality of sleep and morning alertness compared to 27% taking inactive placebo. Importantly there was no rebound insomnia when stopping the use of melatonin sleep aid, and no withdrawal symptoms.
A large analysis of 17 clinical studies involving melatonin concluded that its use increased total sleep time by 12.8 minutes.
Melatonin supplements are often combined with the amino acid, l-theanine, which is what makes a cup of tea so refreshing and relaxing. L-theanine acts as a building block for the production of relaxing brain chemicals, such as GABA, to promote more refreshing sleep.
Melatonin for jet lag
Jet lag is a disturbance in your 24-hour sleep-wake biorhythms due to flying across several time zones. Jet lag is associated with a slow adjustment of melatonin hormone production to produce general disorientation, insomnia, fatigue, headache, irritability, poor concentration and reduced immunity. Travelling East, which shortens a traveller’s day, produces the most severe symptoms, and older people who normally follow an established daily routine are also most affected. Taking melatonin hormone supplements can help.
A gold-standard Cochrane review examined all randomized trials in which travellers who took either melatonin (0.5–5 mg) or placebo at the destination bedtime (10pm to midnight). Nine of the ten trials found that melatonin, taken close to the target bedtime at the destination decreased jet-lag from flights crossing five or more time zones. While all doses were similarly effective, people fell asleep faster and slept better after taking 5mg melatonin than 0.5mg. Benefit was less when flying westward than when flying east.
The timing of the melatonin dose was important – when taken at the wrong time, early in the day, it caused sleepiness and delayed adaptation to local time. The researchers concluded that melatonin is remarkably effective in preventing or reducing jet-lag, and occasional short-term use appeared to be safe.
They did point out that people with epilepsy, and those taking warfarin may come to harm from taking melatonin, however. As always, if you have a medical condition or are taking any prescribed drugs, it is important to seek advice from a doctor or pharmacist before taking a supplement.
Melatonin for anti-ageing
Melatonin is a powerful antioxidant, which neutralises free radicals to reduce oxidative damage associated with ageing. Researchers have found that melatonin also activates sirtuin proteins which are involved in regulating cell ageing, in a similar way to resveratrol, a polyphenol found in red grapes. As melatonin production declines with age, its loss may contribute to some of the degenerative conditions associated with aging, although this is far from proven.
Melatonin has also been found to regulate the function of mitochondria, the battery-like structures that generate energy in almost all body cells (except red blood cells and those in the eye lens). This may make melatonin a powerful protector against a variety of age-related diseases but this is still under investigation.
Melatonin safety and side effects
The UK licensed melatonin product, Circadin, is a prolonged-release formulation. The Patient Information Leaflet advises users not to drink alcohol as this reduces the effectiveness of Circadin on sleep. It also mentions caution in women taking oestrogen (eg contraceptive pills or hormone replacement therapy) which increase melatonin levels by reducing its metabolism. Melatonin tablets should not be used during pregnancy or breastfeeding, by people with liver problems, or autoimmune conditions. However, these warnings are rarely given to people buying melatonin supplements on-line.
What’s more, in clinical trials involving over 3,500 people, almost half (48.8%) of those taking Circadin reported an adverse reaction, of which the most common were headache, nasopharyngitis (sore throat, runny nose), back pain and aching joints (arthralgia).
No serious adverse effects have been reported with melatonin use for up to three months although its long-term safety has not been established. If you have a medical condition or are taking any prescribed drugs, it is important to seek advice from a doctor or pharmacist before taking melatonin supplements as interactions can occur.
How to boost your own melatonin naturally
While melatonin is widely used short-term to aid sleep or relieve jet lag, for long-term sleep problems, it makes sense to naturally increase your own melatonin production. This is particularly helpful for the reduced sleep quality associated with increasing age and reduced melatonin synthesis.
Sour cherries such as Balaton and Montmorency cherries are one of the richest dietary sources of ready-made melatonin hormone. In fact, these sour cherries provide five times more melatonin than other fruit sources such as blackberries and strawberries.
A study involving 20 volunteers tested the effects of drinking either tart cherry juice or a similar tasting placebo for seven days before bedtime. After a break, the same volunteers then switched to the other drink for another seven days. Their melatonin levels were significantly boosted when drinking the cherry juice, but not when drinking the placebo. The real cherry juice helped them get to sleep more quickly and increased their total sleep time. Tart cherry juice drinks or capsules are available from Healthspan (for its other benefit of boosting sports’ performance), Amazon.co.uk and Amazon.com.
5-HTP (5-hydroxytryptophan) is an amino acid that is only found in the human brain, and in the seeds of a West African medicinal plant, Griffonia simplicifolia. Unlike most amino acids 5-HTP is not used as a protein building block throughout the body, but is concentrated within the brain to stimulate the production of brain chemicals, including serotonin (5-hydroxytryptamine or 5-HT) which is converted on to melatonin. 5-HTP also stimulates the synthesis of endorphins and, as well as improving sleep quality, has positive effects on mood, memory, concentration and mental performance. 5-HTP helps to extend the amount of time spent in REM (rapid eye movement, or dreaming) sleep so you wake feeling more refreshed. In some people it may trigger vivid dreams. See the best 5-HTP products at Healthspan.co.uk, Boots, Amazon.co.uk or Amazon.com.
Tryptophan rich foods
Tryptophan rich foods are also supply building blocks to make serotonin and melatonin, and help to regulate your sleep/wake cycle. Foods that are rich in the tryptophan include eggs, turkey, chicken liver, chick peas (garbanzo beans), bananas, oats, honey, pumpkin seeds, spirulina, soy beans, tofu, watermelon seeds, almonds, peanuts, and dairy products (eg semi-skimmed milk, live yoghurt, cottage cheese).
High-protein foods such as meats, fish, beans, lentils, seeds and nuts will also provide useful amounts of tryptophan. Have your turkey and other high protein foods earlier in the day, though, to give them time to get to work, and to avoid indigestion from eating late in the evening.
A study involving 437 older people found that a higher milk or cheese consumption during the day improved the ability to fall asleep at night in those who also engaged in light physical activity. Dairy products promote sleep in several ways. As well as providing tryptophan to boost melatonin synthesis, they also contain good amounts of relaxing minerals (magnesium and calcium) plus peptides (small proteins) that help babies to sleep after suckling. Clinical studies show these peptides (eg lactium) have a significant sleep-inducing and relaxing effect in adults, too, but promoting deep delta-wave sleep.
Contrary to the old wives’ tale, eating cheese is not associated with nightmares – this myth was believed to have arisen from Charles Dickens’ character, Scrooge, who blamed his nocturnal ghostly visitations on eating a ‘crumb of cheese’ before bed.
Drinking a cup of hot milk before bed is a popular sleep aid, which is now known to work partly by providing a ready-made melatonin boost.
Avoid excess caffeine
Caffeine is a stimulant that reduces melatonin production. Drinking excessive amounts of caffeine during the day can suppress melatonin production.Having a caffeine dose equivalent to a double espresso 3 hours before bedtime was found to delay the production of melatonin by around 40 minutes. This delay was nearly half that induced by exposure to 3 hours of evening bright light (3000 lux) however.
Avoid bright light
Exposure to bright artificial light at night disrupts melatonin synthesis and delay the onset of melatonin production by as much as two hours. As a result, melatonin levels are still high around two hours after waking causing significant daytime drowsiness. A group of people with sleep difficulties who spent just one week without artificial light, while camping, showed improved melatonin levels that returned to around 70% of normal after 7 days.
Emerging evidence even suggests that human sleeping patterns are changing as a result of our modern exposure to light. Historian Roger Ekirch of Virginia Tech concluded that our distant ancestors slept in two distinct periods during the night. Instead of one eight-hour period, as today, they started with three or four hours sleep followed by an awake period of around three hours, and then slept again until morning. He believes our natural sleep pattern started to disappear during the late 17th Century with the industrial revolution and the advent of night-lighting. Light is also a factor behind ‘sleep maintenance insomnia’ – a common condition in which you wake in the middle of the night and have trouble getting back to sleep.
His research is backed by earlier experiments in which psychiatrist Thomas Wehr kept 14 volunteers in complete darkness for 14 hours a day over the course of a month. By the fourth week, the participants settled into a very distinct natural sleeping pattern that was identical to that suggested by Ekirch.
Rather than resorting to melatonin tablets to help you sleep, the above diet and lifestyle approaches will help you sleep better by providing a more natural melatonin boost.