Melatonin, the sleep hormone
You probably know melatonin as the sleep hormone.
You may also know that it is linked to the (perceived) drowsiness of a large turkey dinner because melatonin is made from the amino acid tryptophan, of which turkey is one of the best sources. (But it’s more likely the very large meal that makes you sleepy, rather than the turkey).
Tryptophan —converted to—> Serotonin —converted to—> Melatonin
Melatonin is actually a neurohormone secreted by the pineal gland in the brain, and it signals to the brain that it’s time to go to sleep. The body naturally releases this hormone when it thinks it actually is time to go to sleep, i.e. when the sun goes down.
So, when the brain detects, through the eyes, that the sun is going down, the pineal gland secretes melatonin. This happens because of the “blue light effect”, which essentially means that when your eyes see blue-violet light, they think that it’s day time and that you need to be awake and alert. This blue light stops production of melatonin. Over the course of the evening, as the eyes are exposed to less blue-violet light and more red-amber light (think sunset colours), melatonin is produced and released to start getting you drowsy.
You can imagine that this can easily be overridden by exposure to artificial light!
In fact, artificial light at night has been associated with health concerns including cancer, particularly breast cancer.(1) Crazy, hey?
In this one minute video, I give you four quick tips how to mimic that sunset light exposure in the evenings/after dark, so your pineal gland releases melatonin:
NOTE from Leesa: I’ve linked the f.lux app as well as a few other products that can help with this in the “Resources” section below.
Melatonin itself is found in tiny amounts in a few foods, notably tomatoes, walnuts, strawberries and cherries. I haven’t seen any evidence that theses foods make you sleepy, and the amount of melatonin they contain is very small, so this is just an interesting fact. 🙂
Even though melatonin is naturally produced in the brain (and a few other places in the body), ingesting or taking a melatonin supplement sublingually (under the tongue) can also produce the same results.
NOTE from Leesa: This is NOT the case with all compounds naturally produced in the body – think insulin for example; consuming insulin will not have the same effect as when it’s produced by the pancreas, or injected directly into the bloodstream. Mode of entry into the body can be a huge factor in terms of effectiveness.
Despite all of melatonin’s benefits, melatonin supplements have one of the largest numbers of labelled cautions and warnings, so they’re definitely NOT for everyone (see below)!
Benefits of melatonin supplements – Sleep!
Let’s not underestimate the many health benefits to getting enough good quality sleep. Improvements in mood and memory, and even lower risks of several diseases are most likely because of improved sleep (and not melatonin).
Many benefits of melatonin are actually benefits of better sleep! #sleep #melatonin Click To Tweet
For a great, thorough, and science-based book (and 14-day challenge) on improving your sleep, see the book Go To Bed by Sarah Ballentyne, PhD.(2)
Melatonin supplements have proven to reduce insomnia, and are often used to help re-establish sleep patterns for people who do shift work, or are jet lagged.
In situations where external stimuli (sunlight and darkness cycles) and internal stimuli (the internal clock) are not in sync, supplemental melatonin is thought to help re-establish balance.(3)
Not only can it help you get drowsy & fall sleep, but it has also been shown to improve sleep duration and quality.
Remember though, even if you take melatonin supplements to help you sleep, you should still avoid bright lights (particularly blue-violet light) before bed as they can cancel out the sleep-inducing effects.(3)
But melatonin is not a sleep cure-all! If you are having difficulty sleeping, there is actually a lot you can do to adjust your diet and lifestyle, and these may even be more effective in the long run than relying on a melatonin supplement. Things like getting sunshine and exercise during the day, having a calming bedtime routine at a consistent time every day (that excludes blue-violet light), and sleeping at optimal temperatures and in complete darkness, etc.(2)Melatonin supplements can help with sleep, but are not a sleep cure-all! #melatonin #sleep Click To Tweet
Benefits of melatonin supplements – Beyond sleep!
Melatonin has also been shown to have some other health effects beyond sleep.
One example is its antioxidant and anti-inflammatory properties. Melatonin supplements can reduce exercise-induced oxidation as well as inflammatory cytokines.
In fact, according to one test tube study(4), melatonin was a better antioxidant than vitamin C, resveratrol (in red wine), EGCG (in green tea), and alpha-lipoic acid (in vegetables).
It can also be beneficial for several gut issues such as heartburn, reflux and even ulcers.
Melatonin’s help for heartburn and reflux is thought to be because it improves the pressure in the lower esophagus and strengthens the sphincter (circular muscle) at the bottom.(3)
Several studies have also shown that melatonin can help reduce symptoms of tinnitus (ringing in the ears).(3)
Melatonin is currently being studied to look at its potential to help reduce mortality in people with certain types of cancers.(3) NOT as a replacement for medical treatment, but in addition to it.
Another great benefit of melatonin supplements is that they do not appear to induce tolerance (needing higher and higher doses to get the same effect) or addiction (inability to discontinue without horrible side effects); nor do they seem to cause a negative feedback loop with the natural production of melatonin.
Many hormone-type medications, such as corticosteroids for example, tend to trigger the body to produce less and less of that hormone because it recognizes that it’s not needed (because you’re supplying it separately). This is the “negative feedback loop” that seems to not apply to melatonin supplements.
Finally (I may have saved the best for last), melatonin can help you live longer!
Melatonin and the pineal gland are highly associated with longevity. Since melatonin levels decline with age, supplementation can have restorative effects.(3)
Melatonin and your bones
Some studies have shown that melatonin may have a beneficial effect on the bones in three ways:
- It can enhance bone formation by inducing osteoblasts, at the same time inhibiting osteoclasts. (5, 6)
- Being a hormone, melatonin also interacts with key bone-affecting hormones such as parathyroid hormone, estrogen, and calcitonin.(5)
- Melatonin’s antioxidant properties can be another mechanism by which melatonin may help maintain bone health by deactivating free radicals produced during bone resorption, and protecting bone cells from further oxidation.(5, 6)
Just as your brain follows a circadian rhythm to sleep when it’s dark out, the rest of your body does too – even your bones.(5)
LAN = Light At Night
A restoration of the melatonin peak at night by limiting LAN or by supplementing nighttime levels with exogenous melatonin may prove to be of benefit . This idea is supported by rodent studies where melatonin administration enhances bone cell proliferation , increases bone mass [33, 84], and induces new bone growth  and, in fact, shows equal efficacy as an estrogen–progesterone HT at increasing bone density given for 1 yr ; HTs are known for their bone-protective functions through estrogen’s inhibitory actions on osteoclasts[85-87] and progesterone’s stimulatory effects on osteoblasts . In humans, specifically perimenopausal women, nighttime supplementation with melatonin (3 mg) for 6 months restored the equilibrium between bone-resorbing osteoclasts and bone-forming osteoblasts . By maintaining these nocturnal melatonin peaks over one’s lifetime, the risk for osteopenia, osteoporosis, and bone fracture may be reduced significantly.(5)
Overall, additional multicentered, randomized control trials (RCTs) in heterogeneous and susceptible populations (e.g., peri- or postmenopausal women, and elderly men and women) are required to assess the efficacy of melatonin to prevent and/or treat bone loss as described .(5)
DISCLAIMER from Leesa: Many of the benefits of melatonin supplementation listed above, especially the non-sleep related ones, have not been studied enough, are not widely recognized, nor are “approved” uses for melatonin supplements – I recommend you follow the directions for use on your supplement’s label, or speak with your healthcare professional.
Risks of melatonin supplements
Of course, since melatonin helps with drowsiness, this is something that should not be taken before driving, operating machinery, or doing anything that requires you to be alert.(7)
Beyond that, there are a few other things to consider.
First of all, if you need to take melatonin for more than 4 weeks, it’s recommended that you see your doctor, because chronic sleep issues can be a symptom of other conditions that may need to be addressed.(7)
Secondly, since melatonin induces drowsiness, you should not combine it with other products that do the same (i.e. alcohol, other supplements, or medications).(7)
Third, melatonin supplements can interact with several other supplements and medications. Speak with your doctor before taking them if you are already taking anticoagulants, anticonvulsants, blood pressure medications, immunosuppressive medications, sedative, hypnotic or psychotropic medications, or steroids.(7)
This also applies to several conditions such as: asthma, cardiovascular disease, chronic kidney disease, depression, diabetes or hypoglycaemia, hormonal disorder, immune system disease, liver disease, migraine, or seizure disorders.(7)
You should not take melatonin supplements if you are pregnant or breastfeeding.(7)
And finally, there are a few adverse reactions to watch out for. They are: mild gastrointestinal symptoms (nausea, vomiting, or cramping), as well as rare allergic reactions. If either of these occur, stop using the melatonin supplements.(7)Melatonin supplements are NOT for everyone - find out the risks here. #melatonin #sleep Click To Tweet
NOTE from Leesa: If you have experienced an adverse event related to your use of a melatonin (or any) supplement, AND you’re in Canada or the USA, you can report them directly to the health authorities at the links below. Health Canada’s MedEffect link is reference (8), and the FDA’s MedWatch link is reference (9).
How should I take melatonin supplements?
If you’re already doing great work in addressing diet and lifestyle to help your sleep cycle,(2) you might consider melatonin supplements.
The interesting thing about supplementing with melatonin is that it appears that lower doses are actually more effective than higher doses. Most of the information I’ve seen shows that 5-10 mg (or less) works as well or better than any doses over 10 mg (so don’t waste your money by doubling-up!).
Melatonin, taken in the evening (sometimes 30 minutes before sleep, at times up to 4-5 hours before sleep with a higher dose) appears to normalize abnormal circadian rhythms. In order to fix jet lag, supplementation should be timed with the clock of the current time zone.(3)
To help you go to sleep, melatonin should be taken once per day at bedtime.
Also, these supplements are recommendations for adults, not children (if you want to try it with your child, then do it under medical supervision only).
Free f.lux app for computers (I personally use this)
Free Twilight app for androids (I personally use this)
(Amazon affiliate links below)
1 – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375362/
2 – Go To Bed – Sarah Ballentyne
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4 – http://www.ncbi.nlm.nih.gov/pubmed/12662349
5 – http://onlinelibrary.wiley.com/doi/10.1111/jpi.12116/full
6 – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676828/
7 – Health Canada’s Natural Health Product Monographs – Melatonin
8 – http://www.hc-sc.gc.ca/dhp-mps/medeff/report-declaration/index-eng.php
9 – https://www.accessdata.fda.gov/scripts/medwatch/index.cfm?action=reporting.home
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I’m Leesa Klich, MSc., R.H.N.
Health writer – Blogging expert – Research nerd.
I help health and wellness professionals build their authority with scientific health content. They want to stand out in the crowded, often unqualified, market of entrepreneurs. I help them establish trust with their audiences, add credibility to their services, and save them a ton of time so they don’t have to do the research or writing themselves. To work with me, click here.
Awesome post, Leesa! I love all of the evidence.
Thanks Sarah – I love combing through the science of supplements. 🙂