Melatonin 101

By: Charlotte Miller

Melatonin – the famous supplement used for sleeping -has become increasingly popular over the past few years. 

It is often taken orally around bed time to aid in sleep and the most common dosages are 3mg, 5mg, and 10mg pills. Melatonin is a naturally occurring hormone in the body that signals the onset of biological night and sleep (Cajochen et al., 2003). The body’s circadian rhythm is regulated by the suprachiasmatic nuclei (SCN) in the hypothalamus (Zisapel, 2018). It is responsible for waking up the body and telling the body to go to sleep. 

“A neural output signal, generated by the SCN, induces the synthesis of melatonin at night by the pineal gland” (Zisapel, 2018). 

When the signals from the SCN go out to the body, they induce the body’s physiological functions that aid in sleep, such as slower metabolism and bowel movement suppression (Zisapel, 2018). As the body begins to ‘shut down’ and prepare for sleep, the feelings of fatigue and drowsiness take over. People often take melatonin to help them fall asleep, but let’s discuss how melatonin supplements really affect the body. 

Melatonin Supplements 

The body starts to release melatonin when it gets dark outside. It takes about two hours after the initial release for humans to feel the peak effects and fall asleep. If you take melatonin supplements or want to in the future, taking the supplements about two hours before you want to fall asleep is ideal, although in some cases it can work more quickly than two hours. 

The question now is: does melatonin help the body fall asleep, stay asleep, or both? 

Research has shown that depending on the dose, it can take anywhere from twenty minutes to two hours, with peak effects declining after an hour and a half (Zisapel, 2018). Essentially, instant-release melatonin supplements help the body fall asleep, but not stay asleep. Taking an oral supplement twenty minutes to two hours prior to bedtime is ideal. When I do take melatonin, I usually aim to take it around 40 minutes before I want to go to sleep. Since most melatonin supplements from pharmacies are instant release, many people, including myself, are unaware that prolonged-release melatonin (PRM) supplements exist. I personally have never tried prolonged-release melatonin supplements before, have you? PRM supplements are released more gradually in the body for slower absorption. This aims to help the  body stay asleep for a long period of time. Below is the graph that shows the  difference between instant-release (IR) melatonin supplements and prolonged-release melatonin (PMR) supplements. 

 (A) Pharmacokinetics of prolonged‐release (PRM) versus immediate‐release (IR) melatonin 2 mg formulations. Results are mean plasma melatonin levels following drug intake and expressed as % of the AUC (adapted from Zisapel, 2010).

Melatonin Recommendations 

Melatonin supplements should be used for short-term sleep problems like insomnia or jet lag (Hopkins, n.d.). Supplements can be safely used for up to two months with the general recommendation around one month. If sleeping problems persist longer than that, or if supplements are not showing the desired effect after a few days, I would recommend seeing a doctor (Hopkins, n.d.). To be clear: taking a high dose of melatonin is unnecessary. No more than 3mg is needed for promoting sleepiness (Hopkins, n.d.; Zisapel, 2018). My recommendation is a 2mg supplement, it has worked wonders for me!

Reference List:

Cajochen, K. (2003). Role of Melatonin in the Regulation of Human Circadian Rhythms and Sleep. Journal of Neuroendocrinology, 15(4), 432–437.

Hopkins, M. (n.d.). Melatonin for Sleep: Does It Work? Retrieved December 17, 2020, from

Zisapel, N. (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. British Journal of Pharmacology175(16), 3190–3199.

Zisapel, N (2010). Melatonin and sleep. The Open Neuroendocrinol Journal, 3, 85–95.

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