Humans are day-time animals. We actually know this because of how our body secretes the hormones cortisol and melatonin. To regulate your sleep-wake cycle, cortisol from the adrenal glands wakes us up at dawn and decreases all day to its lowest point at dusk. Melatonin starts its secretion from the pineal gland at dusk and maximizes secretion from 2-4AM.
As a supplement, melatonin has become increasingly popular for managing insomnia, jet lag, and disruptions in sleep patterns. However, its widespread use has raised questions about its safety. Can taking melatonin interfere with our body's natural production? Can we become dependent on it? Are there risks associated with long-term supplementation?
Fortunately, several clinical studies and systematic reviews have investigated these questions, and the evidence is reassuring.
What Do Clinical Studies Tell Us About Melatonin Safety?
One of the more comprehensive systemic reviews of melatonin safety was published by Besag and colleagues in 2019. This multi-clinical trial evaluation examined 37 randomized controlled trials investigating adverse events associated with melatonin supplementation. Doses ranged from 0.15 mg to 12 mg daily, with treatment durations extending up to 29 weeks.
Researchers found melatonin was well-tolerated with few adverse events. The most commonly reported side-effects included daytime drowsiness, mild headaches, and dizziness. These were rare, very minor and had no safety concerns for most participants. The authors concluded that melatonin has a favorable safety profile and encouraged long-term studies to be performed (Besag et al., 2019).
What About Higher Doses of Melatonin?
Commercially available melatonin supplements typically contain doses ranging from 1 mg to 10 mg. This raises an important question: Does increasing dose increase risk?
In 2022, Menczel Schrire and colleagues published a systematic review and meta-analysis examining higher-dose melatonin, defined as 10 mg or more daily.
The researchers identified 79 randomized controlled trials involving 3,861 participants. Higher-dose melatonin was not associated with a statistically significant increase in adverse events or treatment discontinuation due to adverse effects. However, nonserious side effects, including headaches, dizziness, and drowsiness, occurred more frequently. These findings suggest that higher doses of melatonin may be reasonably well tolerated in some adults (Menczel Schrire et al., 2022). However, this does not mean that high-dose supplementation is universally safe. Consult a healthcare provider if you think you need to take more than 10 mg of melatonin.
The “more-is-more” idea with melatonin is not sound logic. More melatonin is not necessarily better. There are other avenues to investigate sleep health, and simply increasing a dose of melatonin is misguided. Appropriate timing and individualized dosing may be more important than simply increasing the amount taken.
Will Taking Melatonin Stop Your Body From Making Its Own?
One of the most common concerns about melatonin supplementation is whether taking it regularly will suppress the pineal gland's natural production of melatonin. This is a reasonable question, particularly because supplementation with certain hormones can suppress the body's endogenous production.
This concern is understandable. Certain hormones, when taken externally, can suppress the body's own production through negative feedback mechanisms. For example, testosterone, progesterone and estrogen supplementation suppresses the hypothalamic-pituitary-gonadal axis, reducing natural production. This is actually the mechanism-of-action for birth control pills. Melatonin does not behave in the same manner.
The simple way to investigate physiological dependence is to evaluate what happens when supplementation is discontinued. If someone takes a substance regularly for months or years and then suddenly stops, do they experience withdrawal symptoms such as headaches, mood disturbances, dizziness, or shakiness? Caffeine withdrawal is a great example.
A particularly relevant study was published by Lemoine and colleagues in 2011. Researchers evaluated the long-term use of 2 mg sustained-release melatonin in adults with insomnia over 6–12 months. Investigators found melatonin was well tolerated and did not produce evidence of tolerance, withdrawal symptoms, or rebound insomnia following discontinuation.
Of particular interest, a smaller subgroup underwent evaluation of endogenous melatonin production. The researchers found no evidence that supplementation suppressed the body's natural melatonin secretion (Lemoine et al., 2011). This is an important finding because it suggests that taking supplemental melatonin does not interfere with the pineal gland's ability to produce its own hormone.
Does Melatonin Cause Biochemical Disruption?
Another reasonable concern is whether melatonin supplementation interferes with other endocrine pathways. Melatonin interacts with several physiological systems, including circadian regulation, reproductive signaling, glucose metabolism, and the hypothalamic-pituitary-adrenal axis.
A randomized, placebo-controlled study published by Wade and colleagues in 2010 investigated prolonged-release melatonin in adults with primary insomnia over six months. The researchers evaluated both treatment effectiveness and safety, including selected endocrine parameters.
Endocrine testing, including cortisol, ACTH, TSH, thyroid hormones, prolactin, sex hormones, LH, and FSH, showed no clinically relevant treatment-related differences. The study noted 2 mg prolonged-release melatonin was well tolerated, with no clinically meaningful disturbances in the hormonal parameters assessed. There was also no evidence of significant withdrawal effects following discontinuation (Wade et al., 2010).
The absence of withdrawal effects after prolonged use means that taking melatonin does not send a signal to your body to stop producing it. Endocrine function is not influenced like it is with sex hormones. If this were the case, melatonin would be a prescription and a taper with withdrawal warnings would be discussed as seen in psychiatric medications.
Can You Become Dependent on Melatonin?
Another common concern is whether regular melatonin use creates dependency. Unlike benzodiazepines and certain prescription sleep medications, melatonin does not act primarily through the GABA-A receptor system responsible for many sedative effects and drug-dependence mechanisms. Instead, melatonin primarily activates MT1 and MT2 receptors, which participate in circadian rhythm regulation.
Clinical studies show no signs of physical dependence, clinically significant withdrawal symptoms, or rebound insomnia following discontinuation of melatonin. Both Lemoine et al. (2011) and Wade et al. (2010) reported reassuring findings regarding discontinuation after prolonged-release melatonin treatment.
Melatonin has a low potential for physical dependence compared with several conventional hypnotic medications. However, some individuals may become psychologically accustomed to taking any supplement as part of their bedtime routine. This is far different from physiological dependence. For instance, my son, when he was little, got into a pattern of needing a drink of water before climbing into bed. It got to be a bit of a thing - redirecting him to just go to sleep was important because the habit with drinking water was becoming a fixation. This is not a chemical-dependency, but more of a psychological habit.
I have been like this too with melatonin, feeling the need to take something to fall asleep because I am worried about rumination driving insomnia. This is why often I advise diversity with sleep support - take melatonin one night, magnesium glycinate or magnesium threonate another. This breaks up the habits. Once or twice a week, I will also advise someone to just not take sleep support, perhaps on a weekend when they can sleep in if needed. All this establishes healthy patterns with sleep, rather than being psychologically dependent on anything to fall asleep.
Conclusion: Is Melatonin Safe?
Collectively, these four studies provide substantial evidence that melatonin has a favorable safety profile when used appropriately.
The research demonstrates several important findings:
Melatonin is well tolerated at conventional doses.
Serious adverse events are uncommon in clinical trials.
Mild side effects, including headaches, dizziness, and daytime fatigue were the only things reported, and that was rare.
Clinical studies show no suppression of melatonin production with supplementation.
Melatonin does not produce significant physical dependence, withdrawal symptoms, or rebound insomnia.
Higher doses may increase mild adverse effects.
The available research supports melatonin as a generally safe supplement for adults, particularly for short- to medium-term use. Melatonin can interact with certain medications, including psychiatric medications, sedatives, and immunosuppressive therapies. Individuals with complex medical conditions, pregnant or breastfeeding patients, and children require additional consideration. Talk to your trusted healthcare provider.
Ultimately, melatonin is best understood as a hormone that helps regulate biological timing rather than simply a sedative that induces sleep. When used at appropriate doses and times, it is a valuable tool for circadian rhythm regulation. As with any therapeutic intervention, thoughtful dosing, appropriate timing, and consideration of individual health circumstances is important.
References
Besag, F. M. C., Vasey, M. J., Lao, K. S. J., & Wong, I. C. K. (2019). Adverse events associated with melatonin for the treatment of primary or secondary sleep disorders: A systematic review. CNS Drugs, 33, 1167–1186.
https://pubmed.ncbi.nlm.nih.gov/31722088/Menczel Schrire, Z., Phillips, C. L., Chapman, J. L., Duffy, S. L., Wong, G., D'Rozario, A. L., & Comas, M. (2022). Safety of higher doses of melatonin in adults: A systematic review and meta-analysis. Journal of Pineal Research, 72(2), e12782.
https://pubmed.ncbi.nlm.nih.gov/34923676/Lemoine, P., Garfinkel, D., Laudon, M., Nir, T., & Zisapel, N. (2011). Prolonged-release melatonin for insomnia: A long-term study of efficacy, safety, and withdrawal. Therapeutics and Clinical Risk Management, 7, 301–311.
https://pubmed.ncbi.nlm.nih.gov/21845053/Wade, A. G., Ford, I., Crawford, G., McConnachie, A., Nir, T., Laudon, M., & Zisapel, N. (2010). Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: A randomized placebo controlled trial on age and endogenous melatonin as predictors of efficacy and safety. BMC Medicine, 8, 51.
https://pmc.ncbi.nlm.nih.gov/articles/PMC2933606/