Melatonin: Supplementation, Nutrition, & Jet Lag
- allygallop
- Aug 21
- 10 min read
When athletes ask me about melatonin, they skip over the question of, “what are ways to improve my sleep?” They want to go straight for the supplement versus avoiding holding TikTok six inches from their face for the entire hour leading up to bedtime.
Regardless, melatonin is a hormone our bodies naturally produce, has an important role in the sleep-wake cycle, and can be used as a supplement. Melatonin has other bodily benefits, especially as an antioxidant and its role in the immune system. (1) However, for the purposes of this article, I’m going to focus on sleep.
In this blog, I’m going to review:
What melatonin is.
Melatonin production, feedback loops, and light exposure.
Supplementing with melatonin
Sleep, jet lag, and the athlete
Nutrition interventions for melatonin health
What is Melatonin?
Melatonin is a hormone known for its role in sleep, as melatonin levels begin to increase as darkness sets in. (2)
Melatonin is produced in the pineal gland, a pea-shaped organ located deep in the brainstem, and is the only hormone this gland produces. Other tissues in the body, including the eye’s retina, are capable of producing melatonin, but the pineal gland is the major contributor. (2-3)
What is Melatonin Made From?
Below is an image from Arendt and Aulinas (2022) showing the step-by-step process of how melatonin is made, which begins with the amino acid tryptophan and includes serotonin (a.k.a., 5HT). (3)
Pinealocytes within the pineal gland are responsible for melatonin production. Serotonin production is key to continue down the pathway in becoming melatonin, so keeping serotonin levels high during the day within the pineal gland makes for efficient melatonin production when needed. Into the night, serotonin levels continue to rise. (4)
Within the pineal gland, present are the enzymes needed to advance serotonin into melatonin—including arylalkylanmine N-acetyltransferase (AA-NAT), the rate-limiting step to melatonin formation. (5)
When Does the Pineal Gland Produce Melatonin?
Melatonin is neither stored nor held anywhere, but produced by the pineal gland when stimulated and immediately released to work its magic. (1) So what stimulates it?
The suprachiasmatic nucleus (SCN) acts as the body’s pacemaker for circadian rhythms, one of which being the sleep-wake cycle. The SCN is located in the brain’s hypothalamus, the latter referred to as the brain’s orchestra conductor coordinating hormones throughout the body. (6-7)
The SCN-pineal gland-melatonin connection relies, in part, on light exposure. The eyes’ retinas are located at the back of the eye and receive and send light along the optic nerves and to the SCN via the retinohypothalamic tract. During the day, melatonin levels are kept low, as the SCN is telling the body to be awake. However, when the sun sets, the SCN stimulates the pineal gland to produce and release melatonin, helping the body prepare for sleep. (6, 8)
The enzyme AA-NAT is produced when the sympathetic nervous system activates the pineal gland by increasing circulating levels of norepinephrine (NE). NE levels are therefore highest at night to match the demand for melatonin, which peaks between 12-3am. (1-3, 5-6)
Melatonin’s release is partnered with a reduction in blood pressure and core body temperature, both of which are sleep signals.
Like caffeine, which binds to adenosine receptors in the brain to downplay fatigue (read my article on caffeine here), melatonin binds to receptors in the brain’s SCN, activating the MT1 and MT2 receptors. MT1 has a prominent role in rapid eye movement sleep (REM) whereas MT2 a greater role in non-REM sleep. (6)
Communication pathways throughout the body talk via feedback loops. Once melatonin binds to the receptors, the hormone has a half-life of 1-2 hours. In the absence of melatonin replenishment, a reduction of binding occurs, as does the downstream effects on sleep. (3,6) After melatonin peaks in the early hours, its production begins to decline as the SCN preps the body for its next wake cycle, downregulating melatonin production and receptor binding, and cueing the body for wakefulness.
What If It’s Constantly Dark?
The SCN is still able to dictate a sleep-wake cycle. The presence or absence of light is only one factor.
Arendt and Aulinas (2022) wrote that “the SCN continues to generate rhythmic output without light suppression since it functions as an endogenous oscillator (master pacemaker or clock). The rhythm deviates from 24h and ‘free-runs’ in the absence of the important light time cue. Light-dark cycles serve to synchronize the rhythm to 24h.” (3)
Individuals with blindness still exhibit a circadian rhythm, with some relying on light’s effect on the SCN whereas in others the light is unable to play a role in the presence of an otherwise functioning sleep-wake cycle. (3)
Supplementing with Melatonin
The more-is-better group, chill. The top five melatonin supplements listed on a local chain pharmacy’s website all contained 10 mg of melatonin per dose. Cruz-Sanabria et al. (2024) noted a sweet spot for dosing fell in the 3-4 mg range, finding that 10 mg worked no better than 1 mg. Excessive melatonin dosing may cause desensitization to the MT1 and MT2 receptors, but that melatonin supplementation does not promote dependency. (1,9)
What benefits did the melatonin supplementation show in the Cruz-Sanabria et al. (2024) study?
It took 9.3 fewer minutes to fall asleep.
It kept you asleep for an additional 19.7 minutes (i.e., if you’re only sleeping six hours per night, this additional time isn’t a game changer).
It seemed to be less effective for those struggling with insomnia, although possibly helpful for insomnia management in the Elderly. (1,9)
The timing of supplementation would be 1-3 hours prior to going to bed. It’s not only melatonin being in the body, but it takes time for heightened levels of melatonin to reduce core body temperature and blood pressure needed to stimulate sleep. (1) Two studies from different research groups found that when used closer to bedtime as if it were a sleeping pill, supplementation was not as effective unless taken in higher doses. (2)
Sleep, Jet Lag, and the Athlete
High-quality sleep is vital for athlete development, performance, and recovery. The message for improved sleep shouldn’t solely rely on popping a nightly melatonin pill (and also isn’t recommended to be a daily thing). Supplementation should be considered a downstream recommendation after basic sleep hygiene has been accounted for and in certain scenarios in an otherwise healthy human.
For sleep, a handful of basic hygiene tips include:
Aiming for somewhere between 7-9 hours of sleep per day.
If napping, nap earlier in the day and stick to under ~45 minutes. Daytime naps can factor into the 7-9 hours of daily sleep.
The sleep environment should be dark, quiet, and cool.
Aim to fall asleep and wake up around the same times.
Be mindful of total daily caffeine intake, including caffeine stacking and timing of doses. Read my article on caffeine here.
Avoid alcohol. It may help you relax, but it’s terrible for sleep quality. Read my article on alcohol and sleep here.
Manage stress, as a racing mind can keep you up.
A relaxing nighttime routine can help train the brain that it’s time to settle down. For instance, a small bedtime snack, caffeine-free chamomile tea, and reading.
Avoid blue light exposure in the hour before bed. This includes the TV, laptop, tablet, and phones. A paper book has also been shown a better option compared to a Kindle, the latter having partially suppressed melatonin production in one study. (10)
But what about the quick phase shifting of circadian rhythms when traveling? Jet lag occurs when there’s a mismatch between a new environment and the body’s circadian rhythm, caused by traveling rapidly across time zones. Sleep-related symptoms of jet lag include fatigue, disturbed sleep, hyperinsomnia, and/or insomnia. The more time zones passed, the worse the symptoms tend to be. Regarding the use of melatonin supplementation in the presence of jet lag, Halson (2019) wrote that common dosing regimens include 2-8 mg with eastward travel (a phase advance) to help reduce daytime symptoms and improve one’s sleep (11). Granted, there are other nutrition interventions to consider with travel, so read the full Halson (2019) article here.
Nutrition and Melatonin
Considering all of the above, the two areas I consider then are (a) retinal health for light sensitivity and (b) tryptophan availability for serotonin production.
Retinal Health
Lutein and zeaxanthin are non-provitamin A carotenoids that deposit into the retina of the eye, which has a role in SCN communication.
Both carotenoids are found in foods that to be yellow, orange, or green, and are only found in plants (mainly vegetables). Here are some daily intakes and sources for both:
Lutein: Upwards of 10-20 mg.
Zeaxanthin: Upwards of 2-4 mg.
Food sources: Green leafy vegetables (spinach, kale, lettuce), peppers, zucchini, broccoli, Brussels sprouts, parsley, nectarines, blackberries, avocados, raspberries, gooseberries, kiwi, black currants, and egg yolks (not a plant, but this is due to poultry being fed lutein- or zeaxanthin-containing feed).
Being within the fat-soluble vitamin A family, bioavailability is improved in the presence of fat (e.g., a whole egg omelet with kale and peppers). (12-13)
Of note, there are no federal daily intake goals set for lutein or zeaxanthin. The values above align with research in age-related macular degeneration, in which the two nutrients function as antioxidants (see the AREDS and AREDS2 clinical trials). Whenever I see third-party certified eye health supplements marketed to athletes, the supplements tend to range in those milligram doses. As a reminder: An athlete with normal eye health is not the same as an older adult with already diseased eyes. Apply research responsibly.
Tryptophan Availability
Remember that bedtime snack I wrote about in the sleep hygiene recommendations? Here’s the time to stack sports nutrition messaging. Given the body is about to head into a fast (the actual sleep), a bedtime snack combining carbohydrates with protein is recommended. Nighttime protein has been shown to reduce muscle protein breakdown when asleep (read my article on bedtime dairy here) and carbohydrates are in the mix for promoting sleep and recovery.
Tryptophan is an amino acid that can be looped into this snack, with intakes as low as 1 gram having improvements on sleep latency and quality. (14) Dietary examples include:
Turkey and chicken (white and dark meat).
Cow’s milk and whey protein, both of which are high in alpha-lactalbumin (high in tryptophan).
Canned tuna.
Oats. (14-15)
Jeukendrup and Gleeson (2024) wrote about tryptophan’s movement across the blood-brain barrier (BBB) and how tryptophan shares a BBB receptor with the large neutral amino acids (LNAA)—which have a greater affinity for the transporter than does tryptophan. However, in the presence of carbohydrates, tryptophan movement across the BBB may be improved due to carbohydrate’s effect on insulin and the LNAAs being diverted to the muscles with that insulin action. LNAA includes the branch-chain amino acids, among other. (14)
Taken together, how could you optimize your tryptophan intake? Combine tryptophan-rich sources with carbohydrates. For instance, a simple smoothie with cow’s milk, whey protein isolate powder, raspberries, cherries, and some avocado; an oatmeal bowl with kiwi, blackberries and Greek yogurt made from cow’s milk; a turkey sandwich with spinach on whole-grain oat bread; or a glass of cow’s milk and kiwis. Of honorable mention, both cherries and kiwis naturally contain melatonin. (16)
Key Takeaways
Nutritionally, there aren’t necessarily sleep-specific nutrient guidance to optimize melatonin production. Lutein and zeaxanthin? A varied vegetable and fruit intake is already recommended for general health. Cow’s milk, oats, tuna, and lean poultry? Already advised. If anything, the nutrition section above provides you another reason to eat your plants and lean sources of protein (and kiwis and cherries).
Prior to purchasing melatonin supplements, conduct a fair sleep hygiene assessment: Is there a phone in your face in the hour before bed? Are you coming home from a baseball game or intense workout and trying to fall asleep ASAP (i.e., the bright lights, loud music, and adrenaline are still affecting you)?
With travel, flying eastward one hour or time zone doesn’t warrant melatonin supplementation. There are other ways you can positively and reasonably adjust.
If supplementing, properly plan for it. Keep your dose below ~3-4 mg, take it 1-3 hours before bedtime, and still follow the sleep hygiene guidance. Popping melatonin right before bed after an hour of video games isn’t it.
References
1) Bostock, Sophie. (Host of the Podcast). (2024, August 16). What dose melatonin do? Could it cure my insomnia? [Audio podcast episode]. In The Sleep Scientist. https://www.youtube.com/watch?v=XyU_RLDeqUk
2) Masters, A., Pandi-Perumal, S.R., Seixas, A., Girardin, J.-L., & McFarlane, S.I. (2014). Melatonin, the hormone of darkness: from sleep promotion to ebola treatment. Brain Disord Ther,4(1):1000151. https://pmc.ncbi.nlm.nih.gov/articles/PMC4334454/
3) Arendt, J., & Aulinas, A. (2022, October 30). Physiology of the pineal gland and melatonin. In Endotext [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK550972/
4) Zagrean, A.-M., Chitimus, D.M., Badiu, C., Panaitescu, A.M., Peltecu, G., & Zagrean, L. (2020). Chapter 2 – the pineal gland and its function in pregnancy and lactation. In C.S. Kovacs & C.L. Deal (Eds.), Maternal-fetal and neonatal endocrinology (pp. 15-37). Academic Press. https://www.sciencedirect.com/science/article/abs/pii/B9780128148235000027
5) Savage, R.A., Zafar, N., Yohannan, S., & Miller, J.-M.M. (2024, February 9). Melatonin. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/sites/books/NBK534823/
6) Gobbi, G., & Comai, S. (2019). Differential function of melatonin MT1 and MT2 receptors in REM and NREM sleep. Front Endocrinol,10(87). https://pubmed.ncbi.nlm.nih.gov/30881340/
7) Keay, N. (2008). Hormones, health and human potential: A guide to understanding your hormones to optimize your health and performance. Sequoia Books.
8) National Cancer Institute. (n.d.). retina. National Institutes of Health. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/retina
9) Cruz-Sanabria, F., Bruno, S., Crippa, A., Frumento, P., Scarselli, M., … & Faraguna, U. (2024). Optimizing the time and dose of melatonin as a sleep-promoting drug: a systematic review of randomized controlled trials and dose-response meta-analysis. J Pineal Res,76(5):e12985. https://pubmed.ncbi.nlm.nih.gov/38888087/
10) Chang, A.-M., Aeschbach, D., Duffy, J.F., & Czeisler, C.A. (2014). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proc Natl Acad Sci USA,112(4):1232-1237. https://pmc.ncbi.nlm.nih.gov/articles/PMC4313820/
11) Halson, S.L. (2019). Nutrition for travel: from jet lag to catering. Int J Sport Nutr Exerc Metab,29(2):228-235. https://pubmed.ncbi.nlm.nih.gov/30507257/
12) Hill, Simon. (Host of the Podcast). (2024, December 23). Tips from an Optometrist for Healthier Eyes and Better Vision, Dr. Joseph Allen (Ep. 345). [Audio podcast episode]. In The Proof with Simon Hill. https://theproof.com/tips-from-an-optometrist-for-healthier-eyes-and-better-vision-dr-joseph-allen/
13) Mrowicka, M., Mrowicki, J., Kucharska, E., & Majsterek, I. (2022). Lutein and zeaxanthin and their roles in age-related macular degeneration—neurodegenerative disease. Nutrients,14(4):827. https://pubmed.ncbi.nlm.nih.gov/35215476/
14) Jeukendrup, A., & Gleeson, M. (2024). Sport Nutrition, fourth edition. Human Kinetics.
15) Richard, D.M., Dawes, M.A., Mathias, C.W., Acheson, A., Hill-Kapturczak, N., & Dougherty, D.M. (2009). L-tryptophan: basic metabolic functions, behavioral research and therapeutic interventions. Int J Tryptophan Res,2:45-60. https://pmc.ncbi.nlm.nih.gov/articles/PMC2908021/
16) Doherty, R., Madigan, S., Nevill, A., Warrington, G., & Ellis, J.G. (2023). The impact of kiwifruit consumption on the sleep and recovery of elite athletes. Nutrients,15(10):2274. https://pmc.ncbi.nlm.nih.gov/articles/PMC10220871/
