Melatonin is a naturally occurring hormone produced primarily by the pineal gland in the brain. It plays a significant role in regulating the body’s sleep-wake cycle, also known as the circadian rhythm, by signaling the onset of darkness and promoting sleepiness. This hormone helps to synchronize various physiological processes with the 24-hour environmental day-night cycle. Melatonin is also widely available as an exogenous dietary supplement, which mimics the functions of the body’s natural melatonin to aid sleep.
Natural Melatonin Production Across Ages
The pineal gland synthesizes and secretes melatonin. This process is heavily influenced by light and darkness, with production increasing significantly during the night and decreasing during daylight hours. Melatonin levels in human infants typically establish a regular pattern around the third month after birth, with peak concentrations occurring between midnight and 8:00 am.
As individuals age, their natural melatonin production tends to diminish. Adolescents often experience a shift in the timing of melatonin secretion, leading to delayed sleep and wake times, which can increase their susceptibility to delayed sleep phase disorder. The pineal gland is larger in children, but it shrinks at puberty, indicating age-related changes in its activity.
How Supplemental Melatonin Is Processed Differently
The absorption, distribution, metabolism, and excretion of exogenous melatonin are influenced by factors like liver enzyme activity. Children’s developing liver enzyme systems may process substances, including melatonin, differently compared to mature adult systems. This can affect how quickly the supplement is absorbed and how long it remains active in their bodies.
Children might exhibit different pharmacokinetic profiles, potentially leading to varied blood concentrations and durations of effect even with similar dosages. The route of administration can also influence absorption, with liquid formulations potentially absorbing faster than gummies or tablets. These differences underscore the need for careful consideration when administering exogenous melatonin to pediatric populations.
Unique Responses to Melatonin in Children
Melatonin is often considered for children with certain neurodevelopmental disorders, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), who frequently experience sleep problems. In these groups, melatonin has demonstrated efficacy in advancing sleep onset time and reducing the time it takes to fall asleep. Studies suggest that children with neurodevelopmental disabilities may have lower nocturnal melatonin secretion, which could explain some of their sleep disturbances.
For children with delayed sleep-wake phase disorder, melatonin can help shift the fall-asleep time earlier, especially when taken at appropriate times. While it can help children fall asleep faster, some research indicates that it may also lead to earlier waking times. The impact on total sleep time in children can vary, with some studies showing a modest increase in sleep duration, particularly in those with neurodevelopmental disorders.
Safety, Side Effects, and Usage Guidelines
While short-term use often appears safe, there are limited studies on the long-term effects of melatonin on growth and hormonal development, including puberty. Common side effects reported in children include daytime drowsiness, headaches, dizziness, and mood disturbances. Some children may also experience increased bedwetting or more vivid dreams.
Melatonin is considered a dietary supplement in the United States, meaning it is not as strictly regulated by the Food and Drug Administration (FDA) as prescription drugs. This lack of regulation can lead to variability in product quality and actual melatonin content, with some supplements found to contain significantly more or less melatonin than stated on the label. It is possible for children to ingest excessive amounts of melatonin, especially from appealing gummy forms, potentially leading to gastrointestinal issues or irritability. Therefore, consulting a healthcare professional before administering melatonin to children is strongly recommended to determine appropriate dosage and assess potential interactions with other medications.