The Case Against Routine Melatonin Use in Children and Adults: A Clinical and Physiological Perspective

By Dr. Michael Lonardo, BCDNM, TND, HMD, PhD

Introduction: The Misconception of the "Benign" Sleep Aid

It is worrying that synthetic melatonin is widely and routinely prescribed in modern integrative and clinical practice, and the public misunderstands it, viewing it as a harmless herbal remedy or a safe vitamin supplement.

In fact, melatonin is a powerful neurohormone with a wide range of effects in the body.

A fundamental tenet of naturopathic and natural medicine is Tolle Causam, a principle which emphasizes the need to identify and treat the underlying cause of disease while at the same time respecting the body's inherent ability to regulate itself (Vis Medicatrix Naturae); the simple act of giving exogenous hormones in order to counteract poor sleep hygiene violates this principle.

Pediatric Considerations: Protecting Fragile Neuroendocrine Pathways

The practice of administering nightly melatonin gummies to children presents significant developmental and clinical risks:

1. The Hypothalamic-Pituitary-Gonadal Axis and Pubertal Development Being Disturbed

Children have in their pineal gland a much greater amount of melatonin than adults, and this natural level plays an important regulatory role with regard to the hypothalamic-pituitary-gonadal (HPG) axis. If exogenous melatonin is introduced, it may lead to the suppression of the pulsatile release of gonadotropin-releasing hormone (GnRH) and have an effect on kisspeptin signaling, thereby interfering with sexual maturation and the timing of puberty.

2. The "Magic Pill" Trap and the Basic Principles of Physiology

The difficulties that children experience in falling asleep are mainly due to mismatches between their current environment and their biological needs, for example because of exposure to artificial blue light which interferes with the retinal-pineal pathways, irregular circadian rhythms, sensory overload and fluctuating blood sugar levels. The practice of giving children melatonin gummies each night may imply that they are unable to regulate their sleep on their own without the use of external chemicals, thus obstructing the development of behavioral sleep resilience.

3. Serious Inconsistencies in Dosage and Excessive Exposure

Because melatonin available over the counter is marketed as a dietary supplement and not as a pharmaceutical drug, quality control is inadequate. Analysis by independent organizations of pediatric gummy products has revealed concentrations varying from 74% to almost 350% of the amount stated on the label, together with unlisted degradation products and contaminants such as serotonin. In children whose livers have not yet fully developed phase I and II clearance mechanisms, this results in toxicological stress and increases the risk of accidental toxicity.

Adult Considerations: The Hazards of Chronic Supraphysiological Dosing

Although short-term melatonin use may help mitigate acute circadian misalignment from transmeridian travel, chronic use in adults presents significant physiological challenges:

1. Massive Supraphysiological Overdosing

A normal, healthy human pineal gland generates approximately 10 to 80 micrograms (that is, 0.01 to 0.08 mg) of melatonin every night. By contrast, the majority of over-the-counter adult supplements contain 3 to 10 milligrams, which is about 30 to 100 times the natural amount. When people are exposed chronically to such doses, the MT1 and MT2 receptors become oversaturated and desensitized, the architecture of both REM and non-REM sleep is disrupted, morning grogginess occurs, and the pineal gland ends up being down-regulated.

2. A Disturbance of Metabolism and a Deterioration of Blood Glucose Levels

Melatonin receptors are present in various parts of the body, such as in the pancreatic beta cells. During the night the hormone helps the body to adopt a fasting state by suppressing the release of insulin. If high doses of melatonin are taken within a few hours of eating dinner or after late-night snacks, this can result in temporary insulin resistance. Over time, continuous nocturnal glucose regulation abnormalities lead to a deterioration of metabolic health and raise the chances of developing pre-diabetes and metabolic syndrome.

3. Concealing the Dysregulation of Cortisol and the Underlying Causes

Adult insomnia is very seldom the result of a primary melatonin deficiency; more often it is caused by dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, since high levels of cortisol in the evening prevent the natural release of melatonin. Other possible causes are undiagnosed obstructive sleep apnoea, imbalances in the gut flora that affect the production of neurotransmitters, and systemic deficiencies in micronutrients (for example, magnesium, zinc, and pyridoxal-5-phosphate). Giving patients hormones to relieve the symptoms does not address the underlying inflammation or autonomic imbalance. The American Academy of Sleep Medicine (AASM) advises against the regular use of melatonin for chronic adult insomnia.

Naturopathic Restoration: Rebuilding the Circadian Pacemaker

It is impossible to obtain restful sleep by having hormones administered from outside the body; the aim in a clinical setting should then be to support the body's own circadian biology.

• Establish the biological clock through morning light exposure. The biological clock for the release of melatonin at night can only be established and the suprachiasmatic nucleus (SCN) made to stabilise if a person is exposed to direct sunlight within 30 to 60 minutes of waking.
• Reduce evening light exposure. In order to lessen the effects of evening light, use warm ambient lighting, blue-blocking lenses, or turn off all screens two hours before going to bed.
• Support the biochemical precursors and cofactors involved in melatonin synthesis. Make sure that there is an adequate supply of the biochemical precursors and cofactors needed for the conversion of serotonin into melatonin, including magnesium bisglycinate, vitamin B6, zinc, and methyl donors.
• Support parasympathetic nervous system activation. The nervous system may be downregulated by means of parasympathetic activation, somatic downregulation, contrast hydrotherapy, and various non-hormonal nervine plants, such as chamomile, passionflower, and skullcap, if appropriate.

Clinical Evidence and Peer-Reviewed References

1. Cohen, P. A., Avula, B., Wang, Y. H., Katragunta, K., and Khan, I. (2023). The amount of melatonin and CBD in melatonin gummies available for sale in the United States. JAMA, 329(16), 1401–1402.
2. Lelak, K., Vohra, V., Neuman, M. I., Toce, M. S., and Sethuraman, U. (2022). Pediatric melatonin ingestions—United States, 2012–2021. MMWR, 71(22), 725–729.
3. Boafo, A., et al. (2019). Does the long-term use of melatonin in prepubertal children have an effect on the timing of puberty? A narrative review. Nature and Science of Sleep, 11, 1–10.
4. Sateia, M. J., Buysse, D. J., Krystal, A. D., Neubauer, D. N., and Heald, J. L. (2017). Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline. Journal of Clinical Sleep Medicine, 13(2), 307–349.
5. Tuomi, T., et al. (2016). Increased melatonin signaling is a risk factor for type 2 diabetes. Cell Metabolism, 23(6), 1067–1077.
6. Rubio-Sastre, P., Scheer, F. A., Gómez-Abellán, P., Madrid, J. A., and Garaulet, M. (2014). Acute melatonin administration in humans impairs glucose tolerance in both the morning and evening. Journal of Clinical Endocrinology & Metabolism, 99(10), 3845–3853.
7. Zhdanova, I. V., et al. (2001). Melatonin treatment for age-related insomnia. The Journal of Clinical Endocrinology & Metabolism, 86(10), 4727–4730.