Melatonin (N-acetyl-5-methoxytryptamine) is naturally produced in the pineal gland, regulating the body's sleep-wake cycles in response to light. As the main controller of your body's internal clock, melatonin determines the times of activity and rest for your body, brain, and organs. Its levels decline with age. Available as a supplement, often synthesized in labs, melatonin is commonly used to address sleep disorders such as insomnia and jet lag.

Synthesis of melatonin in vivo.

Melatonin synthesis begins with the conversion of the amino acid L-tryptophan into serotonin, facilitated by enzymes like tryptophan hydroxylase. From there, serotonin is converted into N-acetyl-serotonin and then into melatonin through a series of enzymatic reactions that involve Acetyl-CoA and SAMe. This process can be fueled by dietary sources of tryptophan or supplemented directly with L-tryptophan or 5-HTP. Supplementing with SAMe can bypass initial steps and directly produce melatonin.

Using melatonin for specific conditions

Blindness-related Sleep Disorders: Melatonin aids in improving these disorders in both adults and children.

Delayed Sleep Phase Syndrome: Characterized by a significantly delayed sleep pattern, resulting in later bedtimes and wake-up times. Melatonin helps adults and children fall asleep faster and start sleeping earlier. Consult a pediatrician before giving melatonin to a child.

Insomnia: Melatonin supplementation may prove more advantageous for older adults potentially experiencing melatonin deficiency.

Jet Lag: Melatonin effectively alleviates jet lag symptoms, such as daytime sleepiness and disrupted alertness.

Sleep Disorders in Disabled Children: Small studies suggest melatonin may help. Good bedtime habits should be prioritized; consult a pediatrician before use.

Recommended Dosage

Although there isn't a set standard dosage for melatonin, people usually take between 1 and 5 milligrams about 30 minutes before bedtime to help with sleep. Melatonin supplements come in doses ranging from 200 micrograms to 20 milligrams.

When giving melatonin to children with insomnia, the dosage is typically based on their age: preschoolers may get 1 to 2 milligrams, school-aged children 1 to 3 milligrams, and adolescents 1 to 5 milligrams.

Side Effects

Orally administered melatonin, when consumed in suitable doses, is generally considered safe. However, it may trigger:

• Headaches
• Dizziness
• Nausea
• Drowsiness

Less commonly reported side effects may include temporary feelings of sadness, slight shaking, mild nervousness, stomach discomfort, restlessness, reduced attentiveness, confusion, or feeling lost.

References

[1] Vasey, Clayton et al. “Circadian Rhythm Dysregulation and Restoration: The Role of Melatonin.” Nutrients vol. 13,10 3480. 30 Sep. 2021

[2] Pandi-Perumal, Seithikurippu R et al. “Melatonin antioxidative defense: therapeutical implications for aging and neurodegenerative processes.” Neurotoxicity research vol. 23,3 (2013): 267-300

[3] Claustrat, B, and J Leston. “Melatonin: Physiological effects in humans.” Neuro-Chirurgie vol. 61,2-3 (2015): 77-84