The hormone can be used as a sleep aid and in the treatment of sleep disorders. It can be taken orally as capsules, tablets, or liquid. It is also available in a form to be used sublingually, and there are transdermal patches. There have been few long-term clinical trials in the use of melatonin in humans.
Melatonin was first discovered in connection to the mechanism by which some amphibians and reptiles change the color of their skin. As early as 1917, Carey Pratt McCord and Floyd P. Allen discovered that feeding extract of the pineal glands of cows lightened tadpole skin by contracting the dark epidermalmelanophores. In 1958 dermatology professor Aaron B. Lerner and colleagues at Yale University, in the hope that a substance from the pineal might be useful in treating skin diseases, isolated the hormone from bovine pineal gland extracts and named it melatonin. In the mid-70s Lynch et al. demonstrated that the production of melatonin exhibits a circadian rhythm in human pineal glands. The discovery that melatonin is an antioxidant was made in 1993. The first patent for its use as a low dose sleep aid was granted to Richard Wurtman at MIT in 1995. Around the same time, the hormone got a lot of press as a possible treatment for many illnesses.The New England Journal of Medicine editorialized in 2000: "The hype and the claims of the so-called miraculous powers of melatonin several years ago did a great disservice to a scientific field of real importance to human health. With these recent careful and precise observations in blind persons, the true potential of melatonin is becoming evident, and the importance of the timing of treatment is becoming clear. Our 24-hour society, with its chaotic time cues and lack of natural light, may yet reap substantial benefits."
Melatonin biosynthesis in humans and some other organisms involves four enzymatic steps from the essential dietary amino acid tryptophan, which follows a serotonin pathway. L-tryptophan is first converted to 5-hydroxy-L-tryptophan (5-HTP) by an enzyme, tryptophan 5-hydroxylase. 5-HTP is then decarboxylated (CO2 removal) by 5-hydroxytryptophan decarboxylase to produce serotonin. This point is the rate limiting stage such that further reaction is determined by light-dark conditions. Only in darkness, the key enzyme, aralkylamine N-acetyltransferase (AANAT) is activated and converts serotonin to N-acetyl serotonin, which is ultimately converted to melatonin by the final enzyme, acetylserotonin O-methyltransferase.
In bacteria, protists, fungi, and plants melatonin is synthesized indirectly with tryptophan as an intermediate product of the shikimic acid pathway. In these cells synthesis starts with d-erythrose-4-phosphate and phosphoenolpyruvate, and in photosynthetic cells with carbon dioxide. The rest of the reactions are similar, but with slight variations in the last two enzymes.
In vertebrates, melatonin secretion is regulated by norepinephrine. Norepinephrine elevates the intracellular cAMP concentration via beta-adrenergic receptors and activates the cAMP-dependent protein kinase A (PKA). PKA phosphoryates the penultimate enzyme, the arylalkylamine N-acetyltransferase (AANAT). At daylight, noradrenergic stimulation stops and the protein is immediately destroyed by proteasomalproteolysis. Production is again started in the evening, which is called the dim-light melatonin onset (DLMO).
It is principally blue light, around 460 to 480 nm, that suppresses melatonin, proportional to the light intensity and length of exposure. Until recent history, humans in temperate climates were exposed to few hours of (blue) daylight in the winter; their fires gave predominantly yellow light. The incandescent light bulb widely used in the twentieth century produced relatively little blue light. Wearing glasses that block blue light in the hours before bedtime may decrease melatonin loss. Kayumov et al. showed that light containing only wavelengths greater than 530 nm does not suppress melatonin in bright-light conditions. Use of blue-blocking goggles the last hours before bedtime has also been advised for people who need to adjust to an earlier bedtime, as melatonin promotes sleepiness.
When used several hours before sleep according to the phase response curve for melatonin in humans, small amounts (0.3 mg) of melatonin shift the circadian clock earlier, thus promoting earlier sleep onset and morning awakening.
In vertebrates, melatonin is produced at nighttime by the pineal gland, a small endocrine gland located in the center of the brain but outside the blood–brain barrier. Light/dark information reaches the suprachiasmatic nuclei (SCN) from retinal photosensitive ganglion cells of the eyes. rather than the melatonin signal (as was once postulated). Many animals use the variation in duration of melatonin production each day as a seasonal clock. In animals including humans the profile of melatonin synthesis and secretion is affected by the variable duration of night in summer as compared to winter. The change in duration of secretion thus serves as a biological signal for the organization of daylength-dependent (photoperiodic) seasonal functions such as reproduction, behavior, coat growth and camouflage coloring in seasonal animals. In seasonal breeders that do not have long gestation periods and that mate during longer daylight hours, the melatonin signal controls the seasonal variation in their sexual physiology, and similar physiological effects can be induced by exogenous melatonin in animals including mynah birds and hamsters. Melatonin can suppress libido by inhibiting secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland, especially in mammals that have a breeding season when daylight hours are long. The reproduction of long-day breeders is repressed by melatonin and the reproduction of short-day breeders is stimulated by melatonin. During the night, melatonin regulates leptin, lowering its levels.
Melatonin is identified in many plants including feverfew (Tanacetum parthenium), St John's wort (Hypericum perforatum), rice, corn, tomato, grape and other edible fruits. The physiological roles in plants include regulation of their response to photoperiod, defense against harsh environments, and the function of an antioxidant. It also regulates plant growth by its ability to slow root formation, while promoting above-ground growth.
In animals, the primary function is regulation of day-night cycles. Human infants' melatonin levels become regular in about the third month after birth, with the highest levels measured between midnight and 8:00 AM. Human melatonin production decreases as a person ages. Also, as children become teenagers, the nightly schedule of melatonin release is delayed, leading to later sleeping and waking times. In humans, 90% of melatonin is cleared in a single passage through the liver, a small amount is excreted in urine, and a small amount is found in saliva.
Besides its function as synchronizer of the biological clock, melatonin is a powerful free-radical scavenger and wide-spectrum antioxidant as discovered in 1993. In many less complex life forms, this is its only known function. Melatonin is an antioxidant that can easily cross cell membranes and the blood–brain barrier. This antioxidant is a direct scavenger of radical oxygen and nitrogen species including OH, O2−, and NO. Melatonin works with other antioxidants to improve the overall effectiveness of each antioxidant. Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant. An important characteristic of melatonin that distinguishes it from other classic radical scavengers is that its metabolites are also scavengers in what is referred to as the cascade reaction. Also different from other classic antioxidants, such as vitamin C and vitamin E, melatonin has amphiphilic properties. When compared to synthetic, mitochondrial-targeted antioxidants (MitoQ and MitoE), melatonin proved to be a better protector against mitochondrial oxidative stress.
While it is known that melatonin interacts with the immune system, the details of those interactions are unclear. Antiinflammatory effect seems to be the most relevant and most documented in the literature. There have been few trials designed to judge the effectiveness of melatonin in disease treatment. Most existing data are based on small, incomplete clinical trials. Any positive immunological effect is thought to be the result of melatonin acting on high-affinity receptors (MT1 and MT2) expressed in immunocompetent cells. In preclinical studies, melatonin may enhance cytokine production, and by doing this counteract acquired immunodeficiences. Some studies also suggest that melatonin might be useful fighting infectious disease including viral, such as HIV, and bacterial infections, and potentially in the treatment of cancer.
Melatonin is categorized by the US Food and Drug Administration (FDA) as a dietary supplement. It is sold freely over-the-counter in both the US and Canada without any regulation as a pharmaceutical drug. The Food and Drug Administration (FDA) regulations applying to medications are not applicable to melatonin. However, new FDA rules required that by June 2010 all production of dietary supplements must comply with "current good manufacturing practices" (cGMP) and be manufactured with "controls that result in a consistent product free of contamination, with accurate labeling." The industry has also been required to report to the FDA "all serious dietary supplement related adverse events", and the FDA has (within the cGMP guidelines) begun enforcement of that requirement.
Melatonin has been reported in foods including cherries to about 0.17–13.46 ng/g, bananas and grapes, rice and cereals, herbs, olive oil, wine and beer. When birds ingest melatonin-rich plant feed, such as rice, the melatonin binds to melatonin receptors in their brains. When humans consume foods rich in melatonin such as banana, pineapple and orange the blood levels of melatonin significantly increase.
As reported in the New York Times in May 2011, beverages and snacks containing melatonin are sold in grocery stores, convenience stores, and clubs. The FDA is considering whether these food products can continue to be sold with the label "dietary supplements". On January 13, 2010, they issued a warning letter to Innovative Beverage, creators of several beverages marketed as "relaxation drinks," stating that melatonin is not approved as a food additive because it is not generally recognized as safe.
A bottle of melatonin tablets. Additionally melatonin is available in timed release and in liquid forms.
Melatonin has been studied for insomnia in the elderly. Prolonged release melatonin has shown good results in treating insomnia in older adults (2007). It may improve circadian misalignment and SAD. Basic research indicates that melatonin may play a role in modulating the effects of drugs of abuse such as cocaine.
A 2004 review found that "there was no evidence that melatonin had an effect on sleep onset latency or sleep efficiency" in people suffering from sleep restriction, such as from shift work and rapid transmeridian travel, while it did decrease sleep onset latency in people with a primary sleep disorder and it increased sleep efficiency in people with a secondary sleep disorder.
Short and long term treatment of prolonged-release melatonin was found to be effective and safe, improving sleep latency, sleep quality and daytime alertness in insomnia patients.
In exploratory studies, prolonged-release melatonin has shown sleep quality improvement in patients with chronic schizophrenia as well as in patients with major depressive disorder and treating sleep-wake cycle disorders in children with underlying neurodevelopment difficulties. Additionally, as add-on to antihypertensive therapy, prolonged-release melatonin improved blood pressure control in patients with nocturnal hypertension as shown in a randomised double-blind placebo controlled study.
Melatonin taken in the evening is, together with light therapy upon awakening, the standard treatment for delayed sleep phase disorder (DSPD) and non-24-hour sleep–wake disorder (Non-24) where circadian rhythms are not entrained (biologically synchronized) to the environmental cycle. It appears to have some use against other circadian rhythm sleep disorders as well, such as jet lag and the problems of people who work rotating or night shifts. Melatonin reduces sleep onset latency to a greater extent in people with DSPD than in people with insomnia.
Many totally blind people can control Non-24 by taking small amounts of melatonin in the evening.
Melatonin appears to increase the amount of sleep in people after working night shifts.
A very small dose taken several hours before bedtime in accordance with the phase response curve for melatonin in humans (PRC) does not cause sleepiness but, acting as a chronobiotic (affecting aspects of biological time structure), advances the phase slightly and is additive to the effect of using light therapy upon awakening. Light therapy may advance the phase about one to two-and-a-half hours and an oral dose of 0.3 or 3 mg of melatonin, timed correctly some hours before bedtime, can add about 30 minutes to the ~2 hour advance achieved with light therapy. There was no difference in the average magnitude of phase shift induced by the 2 doses.
Research shows that after melatonin is administered to ADHD patients on methylphenidate, the time needed to fall asleep is significantly reduced. Furthermore, the effects of the melatonin after three months showed no change from its effects after one week of use.
A systematic review of unblinded clinical trials involving a total of 643 cancer patients using melatonin found a reduced incidence of death but that blinded and independently conducted randomized controlled trials are needed. The National Cancer Institute's review of the evidence found that it remains inconclusive.
Melatonin presence in the gallbladder has many protective properties, such as converting cholesterol to bile, preventing oxidative stress, and increasing the mobility of gallstones from the gallbladder. It also decreases the amount of cholesterol produced in the gallbladder by regulating the cholesterol that passes through the intestinal wall. Concentration of melatonin in the bile is 2–3 times higher than the otherwise very low daytime melatonin levels in the blood across many diurnal mammals, including humans.
Protection from radiation
Both animal and human studies have shown melatonin to be potentially radioprotective. Moreover, it is a more efficient protector than amifostine, a commonly used agent for this purpose. The mechanism of melatonin in protection against ionizing radiation is thought to involve scavenging of free radicals. It is estimated that nearly 70% of biological damage caused by ionizing radiation is attributable to the free radical, especially the hydroxyl radical that attacks DNA, proteins, and cellular membranes. Melatonin has been suggested as a radioprotective agent, with the proposed advantages of being broadly protective, readily available, orally self-administered, and without major known side effects.
Several medical studies involving adult patients indicate that melatonin can be beneficial in the treatment of tinnitus.
Some supplemental melatonin users report an increase in vivid dreaming. Extremely high doses of melatonin (50 mg) dramatically increased REM sleep time and dream activity in people both with and without narcolepsy.
While the packaging of melatonin often warns against use in children, available studies suggest that melatonin is an efficacious and safe treatment for ADHD and sleep-onset insomnia. However larger and longer studies are needed to establish long-term safety and optimal dosing.
Melatonin appears to cause very few side-effects in the short term, up to three months, at low doses. A systematic review in 2006 showed that for sleep disorders such as jet lag and shift work, melatonin is not effective although it is safe for short term use". Prolonged-release melatonin is safe with long-term use of up to 12 months.
Melatonin can lower FSH levels. Effects of the hormone on human reproduction remain unclear, although it was with some effect tried as a contraceptive in the 1990s.
Melatonin was thought to have a very low maternal toxicity in rats. Recent studies have found results which suggested that it is toxic to photoreceptor cells in rats' retinas when used in combination with large amounts of sunlight and increases the incidence of tumours in white mice.
In animal models, interventions that increase the bioavailability of melatonin seem to increase the severity of the symptoms of Parkinson's disease, whereas reduction in melatonin by pinealectomy or exposure to bright light can improve recovery from those symptoms. Melatonin may exacerbate neurodegeneration in advanced Parkinson's disease in rats.
The effects of long-term supplementation of melatonin in humans have not yet been thoroughly studied nor ascertained. One prescription-only, prolonged-release melatonin product, trade-name Circadin, 2 mg, is available for up to three months use by people aged 55 and over.
Immediate-release melatonin is scarcely regulated. It is available in doses from less than half a milligram to 5 mg or more. It causes blood levels of melatonin to reach their peak in about an hour. The hormone may be administered orally, as capsules, tablets or as liquid. It is also available for use sublingually, or as transdermal patches.
The legal availability of melatonin varies widely among countries, ranging from being available without prescription (e.g. in most of North America and Finland) to being available only on prescription (e.g. in the European Union, Norway and Australia) or not at all (although its possession and use may not be illegal). Immediate-release melatonin is widely available on the Internet as a dietary supplement.
Formerly, melatonin was derived from animal pineal tissue, such as bovine. It is now synthetic and does not carry a risk of contamination or the means of transmitting viral material.
Melatonin is available as a prolonged-release prescription drug, trade-name Circadin, manufactured by Neurim Pharmaceuticals. Containing 2 mg melatonin, it was shown in clinical trials of older adults to decrease time to fall asleep and improve quality of sleep and daytime functioning.
Circadin 2mg, prolonged-release melatonin
It releases melatonin gradually over 8–10 hours, mimicking the body's internal secretion profile.
The European Medicines Agency (EMA) has approved Circadin for patients aged 55 or over, as monotherapy for the short-term treatment (up to 13 weeks) of primary insomnia characterized by poor quality of sleep.
Other countries' agencies that subsequently approved the drug include:
--the Australian Therapeutics Goods Administration (TGA),
--the Swiss Agency for Therapeutics Products (SwissMedic),
--the South Korean Ministry of Food and Drug Safety (MFDS) and
^Acuna-Castroviejo, D; Escames, G; Tapias, V; Rivas, I (2006). "Melatonin, mitochondria and neuroprotection". In Montilla, Pedro; Túnez, Isaac. Melatonin: Present and Future. New York, US: Nova Science Publishers. pp. 1–33. ISBN9781600213748.
^ abHardeland R (July 2005). "Antioxidative protection by melatonin: multiplicity of mechanisms from radical detoxification to radical avoidance". Endocrine27 (2): 119–30. doi:10.1385/ENDO:27:2:119. PMID16217125.
^Reiter RJ, Acuña-Castroviejo D, Tan DX, Burkhardt S (June 2001). "Free radical-mediated molecular damage. Mechanisms for the protective actions of melatonin in the central nervous system". Ann. N. Y. Acad. Sci.939: 200–15. doi:10.1111/j.1749-6632.2001.tb03627.x. PMID11462772.
^US patent 5449683, Wurtman RJ, "Methods of inducing sleep using melatonin", issued 1995-09-12, assigned to Massachusetts Institute of Technology
^Arendt J (August 2005). "Melatonin: characteristics, concerns, and prospects". J. Biol. Rhythms20 (4): 291–303. doi:10.1177/0748730405277492. PMID16077149. There is very little evidence in the short term for toxicity or undesirable effects in humans. The extraordinary “hype” of the miraculous powers of melatonin in the recent past did a disservice to acceptance of its genuine benefits.
^Hardeland, R. (2014). "Melatonin in plants and other phototrophs: advances and gaps concerning the diversity of functions". Journal of Experimental Botany18 (pii): eru386. doi:10.1093/jxb/eru386. PMID25240067.
^Schomerus, C.; Korf, HW (2005). "Mechanisms regulating melatonin synthesis in the mammalian pineal organ". Annals of the New York Academy of Sciences1057 (1): 372–383. doi:10.1196/annals.1356.028. PMID16399907.
^Brainard GC, Hanifin JP, Greeson JM, Byrne B, Glickman G, Gerner E, Rollag MD (August 2001). "Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor". J. Neurosci.21 (16): 6405–12. PMID11487664.
^Richardson GS (2005). "The human circadian system in normal and disordered sleep". J Clin Psychiatry. 66 Suppl 9: 3–9; quiz 42–3. PMID16336035.
^Perreau-Lenz S, Pévet P, Buijs RM, Kalsbeek A (January 2004). "The biological clock: the bodyguard of temporal homeostasis". Chronobiol. Int.21 (1): 1–25. doi:10.1081/CBI-120027984. PMID15129821.
^Lincoln GA, Andersson H, Loudon A (October 2003). "Clock genes in calendar cells as the basis of annual timekeeping in mammals – a unifying hypothesis". J. Endocrinol.179 (1): 1–13. doi:10.1677/joe.0.1790001. PMID14529560.
^ abArendt J, Skene DJ (February 2005). "Melatonin as a chronobiotic". Sleep Med Rev9 (1): 25–39. doi:10.1016/j.smrv.2004.05.002. PMID15649736. Exogenous melatonin has acute sleepiness-inducing and temperature-lowering effects during 'biological daytime', and when suitably timed (it is most effective around dusk and dawn) it will shift the phase of the human circadian clock (sleep, endogenous melatonin, core body temperature, cortisol) to earlier (advance phase shift) or later (delay phase shift) times.
^Chen HJ (July 1981). "Spontaneous and melatonin-induced testicular regression in male golden hamsters: augmented sensitivity of the old male to melatonin inhibition". Neuroendocrinology33 (1): 43–6. doi:10.1159/000123198. PMID7254478.
^Iriti M, Faoro F (2009). "Bioactivity of grape chemicals for human health". Nat Prod Commun4 (5): 611–34. PMID19445314.
^Tan DX, Hardeland R, Manchester LC, Korkmaz A, Ma S, Rosales-Corral S, Reiter RJ (January 2012). "Functional roles of melatonin in plants, and perspectives in nutritional and agricultural science". J. Exp. Bot.63 (2): 577–97. doi:10.1093/jxb/err256. PMID22016420.
^Tan DX, Hardeland R, Manchester LC, Paredes SD, Korkmaz A, Sainz RM, Mayo JC, Fuentes-Broto L, Reiter RJ (August 2010). "The changing biological roles of melatonin during evolution: from an antioxidant to signals of darkness, sexual selection and fitness". Biol Rev Camb Philos Soc85 (3): 607–23. doi:10.1111/j.1469-185X.2009.00118.x. PMID20039865.
^ abcTan DX, Manchester LC, Terron MP, Flores LJ, Reiter RJ (January 2007). "One molecule, many derivatives: a never-ending interaction of melatonin with reactive oxygen and nitrogen species?". J. Pineal Res.42 (1): 28–42. doi:10.1111/j.1600-079X.2006.00407.x. PMID17198536.
^Carrillo-Vico A, Guerrero JM, Lardone PJ, Reiter RJ (July 2005). "A review of the multiple actions of melatonin on the immune system". Endocrine27 (2): 189–200. doi:10.1385/ENDO:27:2:189. PMID16217132.
^Arushanian EB, Beĭer EV (2002). "[Immunotropic properties of pineal melatonin]". Eksp Klin Farmakol (in Russian) 65 (5): 73–80. PMID12596522.
^Buscemi N, Vandermeer B, Pandya R, Hooton N, Tjosvold L, Hartling L, Baker G, Vohra S, Klassen T (November 2004). "Melatonin for treatment of sleep disorders". Evidence Report/Technology Assessment No. 108. (Prepared by the University of Alberta Evidence-based Practice Center, under Contract No. 290-02-0023.) AHRQ Publication No. 05-E002-2. Rockville, MD: Agency for Healthcare Research and Quality. Agency for Healthcare Research and Quality (AHRQ), US Department of Health and Human Services. Retrieved 5 June 2013.
^Burkhardt S, Tan DX, Manchester LC, Hardeland R, Reiter RJ (October 2001). "Detection and quantification of the antioxidant melatonin in Montmorency and Balaton tart cherries (Prunus cerasus)". J. Agric. Food Chem.49 (10): 4898–902. doi:10.1021/jf010321. PMID11600041.
^Lamont KT, Somers S, Lacerda L, Opie LH, Lecour S (May 2011). "Is red wine a SAFE sip away from cardioprotection? Mechanisms involved in resveratrol- and melatonin-induced cardioprotection". J. Pineal Res.50 (4): 374–80. doi:10.1111/j.1600-079X.2010.00853.x. PMID21342247.
^Hattori A, Migitaka H, Iigo M, Itoh M, Yamamoto K, Ohtani-Kaneko R, Hara M, Suzuki T, Reiter RJ (March 1995). "Identification of melatonin in plants and its effects on plasma melatonin levels and binding to melatonin receptors in vertebrates". Biochem. Mol. Biol. Int.35 (3): 627–34. PMID7773197.
^Sae-Teaw M, Johns J, Johns NP, Subongkot S (October 2012). "Serum melatonin levels and antioxidant capacities after consumption of pineapple, orange, or banana by healthy male volunteers". J. Pineal Res.55 (1): 58–64. doi:10.1111/jpi.12025. PMID23137025.
^Wade AG, Ford I, Crawford G, McMahon AD, Nir T, Laudon M, Zisapel N (October 2007). "Efficacy of prolonged release melatonin in insomnia patients aged 55–80 years: quality of sleep and next-day alertness outcomes". Curr Med Res Opin23 (10): 2597–605. doi:10.1185/030079907X233098. PMID17875243.
^Uz T, Akhisaroglu M, Ahmed R, Manev H (December 2003). "The pineal gland is critical for circadian Period1 expression in the striatum and for circadian cocaine sensitization in mice". Neuropsychopharmacology28 (12): 2117–23. doi:10.1038/sj.npp.1300254. PMID12865893.
^Shamir E, Laudon M, Barak Y, Anis Y, Rotenberg V, Elizur A, Zisapel N (2000). "Melatonin improves sleep quality of patients with chronic schizophrenia". J Clin Psychiatry61 (5): 373–7. doi:10.4088/jcp.v61n0509. PMID10847313.
^Jan JE, Hamilton D, Seward N, Fast DK, Freeman RD, Laudon M (August 2000). "Clinical trials of controlled-release melatonin in children with sleep-wake cycle disorders". J. Pineal Res.29 (1): 34–9. doi:10.1034/j.1600-079X.2000.290105.x. PMID10949538.
^Sack RL, Brandes RW, Kendall AR, Lewy AJ (October 2000). "Entrainment of free-running circadian rhythms by melatonin in blind people". N. Engl. J. Med.343 (15): 1070–7. doi:10.1056/NEJM200010123431503. PMID11027741.
^Liira, J; Verbeek, JH; Costa, G; Driscoll, TR; Sallinen, M; Isotalo, LK; Ruotsalainen, JH (Aug 12, 2014). "Pharmacological interventions for sleepiness and sleep disturbances caused by shift work.". The Cochrane database of systematic reviews8: CD009776. doi:10.1002/14651858.CD009776.pub2. PMID25113164.
^Tjon Pian Gi CV, Broeren JP, Starreveld JS, Versteegh FG (July 2003). "Melatonin for treatment of sleeping disorders in children with attention deficit/hyperactivity disorder: a preliminary open label study". Eur. J. Pediatr.162 (7–8): 554–5. doi:10.1007/s00431-003-1207-x. PMID12783318.
^Gagnier JJ (August 2001). "The therapeutic potential of melatonin in migraines and other headache types". Altern Med Rev6 (4): 383–9. PMID11578254.
^Mills E, Wu P, Seely D, Guyatt G (November 2005). "Melatonin in the treatment of cancer: a systematic review of randomized controlled trials and meta-analysis". J. Pineal Res.39 (4): 360–6. doi:10.1111/j.1600-079X.2005.00258.x. PMID16207291.
^Koppisetti S, Jenigiri B, Terron MP, Tengattini S, Tamura H, Flores LJ, Tan DX, Reiter RJ (October 2008). "Reactive oxygen species and the hypomotility of the gall bladder as targets for the treatment of gallstones with melatonin: a review". Dig. Dis. Sci.53 (10): 2592–603. doi:10.1007/s10620-007-0195-5. PMID18338264.
^Reiter RJ, Herman TS, Meltz ML (December 1996). "Melatonin and radioprotection from genetic damage: in vivo/in vitro studies with human volunteers". Mutat. Res.371 (3–4): 221–8. doi:10.1016/S0165-1218(96)90110-X. PMID9008723.
^Topkan E, Tufan H, Yavuz AA, Bacanli D, Onal C, Kosdak S, Yavuz MN (October 2008). "Comparison of the protective effects of melatonin and amifostine on radiation-induced epiphyseal injury". Int. J. Radiat. Biol.84 (10): 796–802. doi:10.1080/09553000802389678. PMID18979313.
^Shirazi A, Ghobadi G, Ghazi-Khansari M (July 2007). "A radiobiological review on melatonin: a novel radioprotector". J. Radiat. Res.48 (4): 263–72. doi:10.1269/jrr.06070. PMID17641465.
^Hurtuk A, Dome C, Holloman CH, Wolfe K, Welling DB, Dodson EE, Jacob A (July 2011). "Melatonin: can it stop the ringing?". Ann. Otol. Rhinol. Laryngol.120 (7): 433–40. PMID21859051.
^Lewis, Alan (1999). Melatonin and the Biological Clock. McGraw-Hill. p. 23. ISBN0-87983-734-9.
^Braam W, Smits MG, Didden R, Korzilius H, Van Geijlswijk IM, Curfs LM (May 2009). "Exogenous melatonin for sleep problems in individuals with intellectual disability: a meta-analysis". Dev Med Child Neurol (Meta-analysis) 51 (5): 340–9. doi:10.1111/j.1469-8749.2008.03244.x. PMID19379289.
^ abBendz LM, Scates AC (January 2010). "Melatonin treatment for insomnia in pediatric patients with attention-deficit/hyperactivity disorder". Ann Pharmacother44 (1): 185–91. doi:10.1345/aph.1M365. PMID20028959.
^Zhdanova IV, Wurtman RJ, Regan MM, Taylor JA, Shi JP, Leclair OU (October 2001). "Melatonin treatment for age-related insomnia". J. Clin. Endocrinol. Metab.86 (10): 4727–30. doi:10.1210/jc.86.10.4727. PMID11600532.
^Srinivasan V, Spence WD, Pandi-Perumal SR, Zakharia R, Bhatnagar KP, Brzezinski A (December 2009). "Melatonin and human reproduction: shedding light on the darkness hormone". Gynecol. Endocrinol.25 (12): 779–85. doi:10.3109/09513590903159649. PMID19905996.
^Cohen M, van Heusden AM, Verdonk HER, Wijnhamer P (1993). "Melatonin/Norethisterone contraception". In Touitou Y, Arendt J and Pevet P. Melatonin and the Pineal Gland – From Basic Science to Clinical Application. Amsterdam: Elsevier. pp. 339–45. ISBN978-0-444-89583-7.
^Jahnke G, Marr M, Myers C, Wilson R, Travlos G, Price C (August 1999). "Maternal and developmental toxicity evaluation of melatonin administered orally to pregnant Sprague-Dawley rats". Toxicol. Sci.50 (2): 271–9. doi:10.1093/toxsci/50.2.271. PMID10478864.
^Anisimov VN, Zavarzina NY, Zabezhinski MA, Popovich IG, Zimina OA, Shtylick AV, Arutjunyan AV, Oparina TI, Prokopenko VM, Mikhalski AI, Yashin AI (July 2001). "Melatonin increases both life span and tumor incidence in female CBA mice". J. Gerontol. A Biol. Sci. Med. Sci.56 (7): B311–23. doi:10.1093/gerona/56.7.B311. PMID11445596.
^Schernhammer E, Chen H, Ritz B (May 2006). "Circulating melatonin levels: possible link between Parkinson's disease and cancer risk?". Cancer Causes Control.17 (4): 577–582. doi:10.1007/s10552-005-9002-9. PMID16596313.
^Meng T, Zheng ZH, Liu TT, Lin L (May 2012). "Contralateral retinal dopamine decrease and melatonin increase in progression of hemiparkinsonium rat". Neurochem Res.37 (5): 1050–6. doi:10.1007/s11064-012-0706-4. PMID22252727.