Melatonin is a hormone secreted by the pineal gland in the brain. It is primarily secreted during the nighttime hours and is best known for supporting healthy sleep in the human body. Tryptophan is a precursor to the endogenous production of melatonin.

Melatonin is believed to support sleep through its ability to restore the sleep/wake cycle, improve sleep quality and daytime activity, and support physiological sleep structure in individuals with insomnia. Melatonin has been shown to support healthy immune function and the body’s response to oxidative stress. It is also believed to be involved in pathways related to aging, stress response, and psycho-neuroendocrine immunology in the human body.

Research has shown melatonin to be a nitric oxide (NO) scavenger and reduce the production of many pro-inflammatory cytokines, including interferon-gamma, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and cyclooxygenase-2 gene expression. In this animal study, an assessment was made on the effects of derivatives of melatonin on murine populations with induced inflammatory conditions. It was found that derivatives of melatonin significantly attenuated the production of pro-inflammatory mediators IL-6, prostaglandin E2, and NO in a dose-dependent manner. In addition, a review of clinical trials reported that melatonin was shown to significantly reduce C-reactive protein in individuals with metabolic syndrome and related disorders.

A recently published systematic review and meta-analysis explored the effect of melatonin on neurocognition in healthy adults and those with insomnia and Alzheimer’s disease (AD). Insomnia has been shown to alter attention, episodic memory, and may be associated with an increased risk of AD. The study reported improvements in cognition without safety concerns or daytime cognitive performance impairment when compared with a placebo. For individuals with AD, supplementation with melatonin showed improvements in cognition, particularly in milder cases. Assessments were made using the Mini-Mental State Examination that indicated greater improvements in cognition when supplementation lasted longer than 12 weeks and in individuals with AD and insomnia as comorbidities. Both immediate and sustained-release formulas were included in the review and both were theorized in the study to support the body’s response to oxidative stress in similar ways. Further research regarding the similarities and potential differences between immediate and sustained release could yield additional conclusions regarding the support of cognitive function.

The research regarding the health-supportive actions of melatonin is evolving, and evidence suggests that it has more actions beyond support for sleep. Supplementation with melatonin may support brain health, cognitive function, and the body’s response to oxidative stress.

By Colleen Ambrose, ND, MAT