Although a role for melatonin as a plant hormone has not been clearly established, its involvement in processes such as growth and photosynthesis is well established. Only limited evidence of endogenous circadian rhythms in melatonin levels has been demonstrated in some plant species and no membrane-bound receptors analogous to those known in animals have been described. Rather, melatonin performs important roles in plants as a growth regulator, as well as environmental stress protector. It is synthesized in plants when they are exposed to both biological stresses, for example, fungal infection, and nonbiological stresses such as extremes of temperature, toxins, increased soil salinity, drought, etc. [39] [85] [86] Melatonin levels then continue to increase as your child ages, reaching peak levels right before puberty. Once puberty hits, there’s a steady decrease in melatonin levels until it evens out in the late teens. In all ages after puberty, melatonin levels are higher in women and people assigned female at birth (AFAB) than in men and people assigned male at birth (AMAB). FDA 101: Dietary Supplements. U.S. Food and Drug Administration (FDA). Accessed May 3, 2021 at https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm050803.htm Ardura J, Gutierrez R, Andres J, Agapito T (2003). "Emergence and evolution of the circadian rhythm of melatonin in children". Hormone Research. 59 (2): 66–72. doi: 10.1159/000068571. PMID 12589109. S2CID 41937922.

Jet lag. Evidence shows that melatonin can improve jet lag symptoms, such as alertness and daytime sleepiness. Bahrampour Juybari K, Pourhanifeh MH, Hosseinzadeh A, et al. Melatonin potentials against viral infections including COVID-19: current evidence and new findings. Virus Research. 2020;287:198108. are often given based on the child’s age. Preschool children are often given a 1 to 2 milligram dose, school-aged children are often given a 1 to 3 milligram dose, and adolescents are often given a 1 to 5 milligram dose. Does melatonin help you sleep? When taken as a supplement, its function is to mimic the effects of the natural sleep hormone. Drowsiness generally occurs within 30 minutes after taking a dose. Different factors cause the decline in age-related melatonin production, including calcification of your pineal gland, which is very common, and issues with light detection due to eye conditions, such as cataracts.Children with chronic sleep-onset insomnia fell asleep 24 minutes earlier and slept 25 minutes longer.

Poeggeler B, Saarela S, Reiter RJ, Tan DX, Chen LD, Manchester LC, Barlow-Walden LR (November 1994). "Melatonin—a highly potent endogenous radical scavenger and electron donor: new aspects of the oxidation chemistry of this indole accessed in vitro". Annals of the New York Academy of Sciences. 738 (1): 419–20. Bibcode: 1994NYASA.738..419P. doi: 10.1111/j.1749-6632.1994.tb21831.x. PMID 7832450. S2CID 36383425. a b Tordjman S, Chokron S, Delorme R, Charrier A, Bellissant E, Jaafari N, Fougerou C (April 2017). "Melatonin: Pharmacology, Functions and Therapeutic Benefits". Current Neuropharmacology. 15 (3): 434–443. doi: 10.2174/1570159X14666161228122115. PMC 5405617. PMID 28503116. Melatonin can be effective for jet lag for many people when dosed at the appropriate time. Studes measuring the effectiveness of melatonin for the treatment of insomnia show a slight reduction in the amount of time needed to fall asleep, but melatonin may not increase the overall quality of sleep. This medication does appear to be safe for short-term use for primary insomnia (less than three months). For Other Conditions Faraone SV (2014). ADHD: Non-Pharmacologic Interventions, An Issue of Child and Adolescent Psychiatric Clinics of North America, E-Book. Elsevier Health Sciences. p.888. ISBN 978-0-323-32602-5.Hypermelatoninemia happens when you have higher-than-normal peak nighttime melatonin levels, usually with an extended duration into the morning (daylight), when compared with what’s expected for your age and sex. The Sleep Foundation editorial team is dedicated to providing content that meets the highest standards for accuracy and objectivity. Our editors and medical experts rigorously evaluate every article and guide to ensure the information is factual, up-to-date, and free of bias. Studies have revealed that supplemental melatonin can improve sleep in specific cases, but it isn’t for everyone. It’s important to talk to your healthcare provider about melatonin supplements first before taking them and to be aware of issues related to side effects and proper dosages. In addition, as the FDA doesn’t regulate dietary supplements, you should be aware of the potential differences in quality from brand to brand. Studies show that this means the actual melatonin content could be below what a product claims. It also means it could be well above what the label claims, and that could lead to side effects. One study showed melatonin content found across 31 supplements ranged from 83% less than advertised up to 478% more than advertised. Chaturvedi CM (1984). "Effect of Melatonin on the Adrenl and Gonad of the Common Mynah Acridtheres tristis". Australian Journal of Zoology. 32 (6): 803–09. doi: 10.1071/ZO9840803.