As the sun goes down and darkness spreads all around, your brain starts to send signals that it is time to sleep. At this signal, the pineal gland located deep within your brain begins to secrete melatonin in the bloodstream. The increased levels of melatonin in the blood send signals to the brain to become less active and make you feel sleepy. You soon enter into a series of complex physical and mental states, which calms your body and slows your body functions, and soon you go to sleep. Melatonin secretion peaks in the middle of the night, ensuring a deep sleep state. As the night passes into the second half, its production starts to decrease. As night gives way to daylight, the reverse process takes place as your body functions start to become gradually active. And soon, you wake up bright and cheerful after a restful night of sleep1.
What is Melatonin?
Melatonin is a natural hormone produced in the human body. It is produced by various tissues in the body, although the major source is the pineal gland in the brain. Melatonin appears to be an important hormone for human physiology, as it has a range of different effects when its concentration level in the bloodstream changes naturally or because you have taken it as a supplement. Melatonin helps to regulate your sleep cycle. It tells your body when it is time to go to sleep and when it is time to wake up. That is why it is also called the sleep hormone, as it regulates your sleep-wake cycle.
Human Circadian Clock
There is a biological master clock in humans and other mammals which controls the daily rhythms of the body. This clock located deep in the brain continuously oscillates throughout the day and night. It is synchronized to the solar day via light perceived by the brain through the eyes. The brain clock is linked with different organs through various pathways of the nervous system. In addition to its daily or circadian rhythm, the body has a seasonal or circannual clock rhythm, which is synchronized with the various seasons of the year. Higher levels of melatonin are produced by the pineal gland in the autumn and winter, when nights are longer, as people generally sleep more, and lower levels are produced when there is less requirement of sleep during spring and summer.
Melatonin and the Circadian Cycle
The pineal gland produces and releases melatonin with a clear daily rhythm, which peaks at night. It is delivered into the bloodstream, the fluid around the brain and the spinal cord. It also sends the hormone to various body organs by the circulation of blood. Tissues proteins called receptors specific for melatonin can detect the levels of melatonin at night, which signals to the body that it is sleep time. Night-time levels of melatonin are at least 10-times higher than daytime concentrations2. As the day breaks, the brain sends the signal to the pineal gland to stop releasing melatonin.
Uses of Melatonin Supplements
For some people, for various reasons, it is difficult to fall asleep. Night-time melatonin secretion is inhibited due to too much ambient artificial light in our rooms, and by the use of computers, laptops, and smartphones before bedtime, as their harsh light reaching the eyes sends confusing signals to the circadian clock, which disturbs sleep patterns.
To overcome this problem, a melatonin supplement may be used to treat sleep disorders. This disorder is commonly called insomnia, which is the difficulty of falling asleep and staying asleep for the required amount of time. Melatonin is often called the sleep hormone for a good reason. It is one of the most popular sleep aids and a common natural remedy to treat insomnia.
Melatonin is also quite effective in resetting the biological clock, which you experience after long-distance airplane travel covering many different time zones. This phenomenon is commonly called jetlag, can result in sleeplessness and general fatigue. Oral melatonin taken in pill form helps to prevent or treat jet lag for passengers and flight crews.
Shift workers who have to work at night typically suffer from sleeping disorders. They are sleepy and disoriented at work but still do not get good sleep when they need it at home. Melatonin can help the shift workers and regulate their sleep patterns to match their work schedules. These workers include hospital and hotel staff, airline and transport industry personnel, police, and other emergency workers.
Melatonin is an antioxidant that removes free radicals and has numerous other properties, such as boosting the immune system. It is also helpful to treat sleep problems in children with autism or other pervasive developmental disorders. It is also used to reduce the effects of fibromyalgia and emotional or mental distress in adults.
How can Melatonin be Used?
Melatonin is available as a supplement in pill form. Natural melatonin is obtained from the pineal gland of animals. It can also be produced chemically and supplied in pill form. Melatonin taken as a supplement mimics the effects of naturally occurring melatonin. Melatonin is classed as a supplement which means it is available without a prescription from pharmacies and nutrition stores. Melatonin is also available as topical creams and lotions.
Topical use of Melatonin
Melatonin penetrates the outer layer of skin, reinforcing the skin’s capacity for repair and revitalization during the night6. Very low concentrations of melatonin are needed for this action. Melatonin’s chemical structure is such that it passes through cell membranes with relative ease, especially when its permeation can be enhanced with agents that reduce its lag time into the skin7.
Melatonin has become the latest popular skincare ingredient that helps to rejuvenate your skin. Melatonin, on entering the skin, quickly kick-starts the production of antioxidant enzymes, which help to block free radicals and thus repair oxidative damage to the skin. In this way, melatonin acts as a skin protectant, which supports free radical scavenging and DNA damage repair3.
Melatonin has potent anti-inflammatory properties that reduce swelling, redness, and other skin conditions. Although the Ultra Violet (UV) part of sunlight has beneficial effects on human skin by increasing vitamin D and endorphins levels, excessive exposure to UV entails serious health risks. Melatonin significantly prevents damage associated with UV irradiation. Melatonin cream protects against sunlight-induced skin inflammation4. Melatonin also has excellent beneficial anti-aging effects on the skin and leads to a reduction in wrinkle formation and therefore, it is now available in beauty creams as an active ingredient.5,8
Melatonin products are mostly used at night when the skin repair process works efficiently. But melatonin also increases antioxidant levels in the skin, which protects the skin from damage; therefore, its use is recommended in the daytime as well when your skin is exposed to excessive sunlight. Skincare professionals suggest applying a sun blocker with melatonin as an important part of your morning skincare routine.
Absorption of Melatonin through the Skin
Delivery of melatonin through the skin by topical use during the daytime can increase plasma melatonin levels and reduce pre-mature waking up after the onset of the sleep phase by ensuring peaceful sleep in the latter part of an 8-hour sleep period. Topical application of melatonin may have certain advantages over fast-release oral melatonin dose in improving sleep maintenance at adverse circadian phases, especially for shift workers10, 11.
Oral melatonin use by pill has a limitation. If the treatment goal is to maintain daytime sleep of about 8 hours, the short elimination half-life of melatonin levels which is about 40 minutes, is a problem. Melatonin levels decrease significantly when its sleep-promoting effect is required most. This is the time when sleep pressure has decreased, and the circadian wake drive starts to increase. If a high oral dose of melatonin is given, then it leads to desensitization of the melatonin receptors, and the body develops tolerance, and good sleep is not maintained.
Melatonin can be delivered through the skin by creams and lotions that can be applied topically. However, a greater improvement over oral delivery of melatonin is a controlled-release transdermal delivery method using a skin patch that has been tested successfully. This allows for delivery of too that the plasma levels steadily increase over a period of 6 to 8 hours instead of decreasing levels as in the case of a pill. The delivery of melatonin by a skin patch inhibits the circadian wake push and improves daytime sleep.
Safety of Melatonin
Melatonin is considered safe for most adults when taken orally for a short term9. It can cause some minor side effects such as dizziness, depression, and headaches, etc. Topical use of melatonin is also considered safe for most adults when applied directly to the skin9.
Not much data is available for the safety of melatonin for children. However, the supplements in reasonable doses appear to be safe for most children for short-term use. Since melatonin is a hormone, its use as a supplement for children could affect their hormonal development during puberty, including menstrual cycles in girls; therefore, its use should take all these factors into account.
Melatonin is a natural human hormone produced within the body in the pineal gland in the brain. It can also be synthesized chemically and used as a supplement. Its main use is to improve sleep quality and reduce the effects of jet lag and can be used orally as a pill. It is also used topically as a cream or lotion as part of a skincare product as it is readily absorbed in the skin. It improves sleep quality and also reduces skin wrinkles and inflammation with additional anti-aging characteristics.
Rusanova I, Martínez-Ruiz L, Florido J, et al. Protective Effects of Melatonin on the Skin: Future Perspectives. Int J Mol Sci. 2019;20(19):4948. Published 2019 Oct 8. doi:10.3390/ijms20194948
4. Scheuer, C.; Pommergaard, H.C.; Rosenberg, J.; Gögenur, I. Dose dependent sun protective effect of topical melatonin: A randomized, placebo-controlled, double-blind study. J. Dermatol. Sci. 2016, 84, 178–185.
5. Zouboulis, C.C.; Adjaye, J.; Akamatsu, H.; Moe-Behrens, G.; Niemann, C. Human skin stem cells and the ageing process. Exp. Gerontol. 2008, 43, 986–997
6. Fischer TW, Greif C, Fluhr JW, Wigger-Alberti W, Elsner P. Percutaneous penetration of topically applied melatonin in cream and alcoholic solution. Skin Pharmacol Physiol. 2004 Jul-Aug;17(4):190-4.
7. Costa EJ, Lopes RH, Lamy-Freund MT. Permeability of pure lipid bilayers to melatonin. J Pineal Res. 1995 Oct;19(3):123-6.
Day D, Burgess CM, Kircik LH. Assessing the Potential Role for Topical Melatonin in an Antiaging Skin Regimen. J Drugs Dermatol. 2018 Sep 1;17(9):966-969. PMID: 30235383.
Bangha E, Lauth D, Kistler GS, Elsner P. Daytime serum levels of melatonin after topical application onto the human skin. Skin Pharmacol. 1997;10(5-6):298-302. doi: 10.1159/000211518. PMID: 9449169.
Aeschbach D, Lockyer BJ, Dijk DJ, et al. Use of transdermal melatonin delivery to improve sleep maintenance during daytime. Clin Pharmacol Ther. 2009;86(4):378-382. doi:10.1038/clpt.2009.109