Melatonin side effects

Melatonin supplements are widely used as a natural sleep aid, particularly for those struggling with insomnia or jet lag. But like any supplement, melatonin isn’t entirely risk-free. Although side effects are typically mild and rare, understanding the potential risks and precautions is crucial before incorporating it into your routine. This guide explores melatonin’s side effects, safety considerations, and what you need to know for informed use.

Key takeaways

• Melatonin side effects are generally mild and infrequent, including daytime drowsiness, nausea, dizziness, and headaches.
• Research on the long-term use of melatonin is still limited.
• Pregnant or breastfeeding individuals and those with underlying medical conditions should consult their doctor before using melatonin.
• Melatonin supplements are safe for most people, but interactions with medications are possible.

What is melatonin?

Melatonin is a hormone naturally produced by the pineal gland in the brain. It helps regulate sleep-wake cycles, also known as circadian rhythms. The body typically produces melatonin in response to darkness, signalling it’s time for sleep [1].

Supplemental melatonin, available in tablets, capsules, liquid forms and now a soluble oral patch, is often used to address sleep disorders like insomnia and jet lag.

Common side effects of melatonin

While melatonin is generally considered safe, some people may experience side effects. These are usually mild and temporary but can vary from person to person [2].

1. Daytime sleepiness: One of the most common side effects is feeling groggy or drowsy during the day. This typically occurs if the dosage is too high or if melatonin is taken too late at night.
2. Headache: Mild headaches can occur as a side effect of melatonin supplementation. If headaches persist, consider adjusting the dose or consulting a healthcare provider.
3. Nausea: Some individuals report feeling nauseous after taking melatonin. Taking the supplement with food may help reduce this side effect.
4. Dizziness: Dizziness can occur, particularly if melatonin is taken in high doses or combined with other medications that cause drowsiness.

Less common side effects of melatonin

Though rare, some people may experience less common side effects when taking melatonin, including irritability or mood swings, stomach cramps, vivid dreams or nightmares, and short-term depression symptoms [2]. If you experience any of these, stop taking melatonin and consult your doctor for advice.

Melatonin in children

Due to melatonin’s popularity and the fact that it can be purchased over the counter in many countries, such as the US, more and more children are being given melatonin supplements to help them sleep [3].

With this background, the Public Safety Committee and Public Awareness Advisory Committee of the American Academy of Sleep Medicine developed a health advisory addressing the use of melatonin in children [4]. They issued the following guidance:

1. Melatonin should be handled like any other medication and kept out of reach by children.
2. Parents should discuss this decision with a paediatric healthcare professional before starting melatonin or any supplement in their children. Many sleep problems can be better managed by changing schedules, habits, or behaviours rather than taking melatonin.
3. If melatonin is used, the health care professional can recommend the melatonin dose and timing for the sleep problem.

Melatonin use has become much more common over the last 20 years for people of all ages. In fact, after multivitamins, it’s the second most popular “natural” supplement parents give their children [5].  

This widespread availability of melatonin in the US has led to melatonin becoming the most frequently ingested substance among children reported to national poison control centres in 2020 [6].

More research is needed to understand how it affects children in both the short and long term.

Side effects of melatonin in children

So far, studies suggest that some children may experience short-term side effects like:

• Headaches
• Feeling dizzy or overly sleepy
• Restlessness or agitation
• Needing to pee more at night or bedwetting

We still don’t know enough about the long-term effects. Some experts worry that melatonin could affect hormone levels or interfere with puberty, but more research is needed to be sure.

If you’re thinking about giving melatonin to your child, it’s important to speak with their doctor first. Melatonin might help with certain sleep issues, like insomnia or delayed sleep patterns, but it’s not recommended for healthy children who have trouble falling asleep now and then.

Doctors usually suggest trying healthy sleep habits and lifestyle changes before using melatonin.

How safe is melatonin?

Melatonin is generally safe for short-term use in adults, but it’s not the right choice for everyone. Some people may need to be extra careful or talk to a doctor before using it—especially if they have health conditions or take certain medications [7].

Here are some groups who should check with a healthcare professional before using melatonin:

• People with kidney or liver problems: Your body may not process melatonin properly, which could increase the risk of side effects.
• Pregnant or breastfeeding individuals: There isn’t enough research to confirm if melatonin is safe during pregnancy or while nursing.
• Older adults with dementia: In this group, the risks may outweigh any benefits, so melatonin is usually not recommended.
• People with mental health conditions: Melatonin might cause or worsen symptoms of depression or other mood issues in some individuals.
• People with immune system conditions: Melatonin can affect the immune system, so those with autoimmune disorders or taking immune-suppressing medication should speak with their doctor.
• People taking medications:  Melatonin can interact with medications—like blood thinners—so if you’re taking prescription drugs, it’s best to get medical advice before trying melatonin.

Is long-term use of melatonin safe?

The long-term effects of melatonin use are not yet fully understood. Most studies have focused on short-term use, generally up to three months [8]. Hence, other treatments for long-term insomnia, such as Quviviq [9], are more suitable.

For this reason, it’s recommended that melatonin be used for short periods unless otherwise advised by a healthcare provider.

Some research suggests that prolonged use in children may affect hormonal development and may delay puberty [10]. So, parents should consult a paediatrician before administering melatonin to their children.

Tips for using melatonin safely

To minimise side effects and maximise benefits, follow these tips:

• Start with a low dose: Begin with the lowest effective dose, typically melatonin 1-3 mg, and adjust as needed.
• Take it at the right time: Melatonin works best when taken 30-60 minutes before bedtime.
• Avoid mixing with alcohol: Alcohol can interfere with melatonin’s effectiveness and increase the risk of side effects.
• Short-term use: Use melatonin for short durations unless instructed otherwise by a healthcare provider.

Why choose a compounded melatonin-soluble oral patch?

Looking for a smarter way to improve your sleep? The compounded melatonin oral patch is a modern, fast-acting option designed to help you fall asleep quickly and stay asleep longer.

This innovative patch is placed inside the mouth, where it dissolves and delivers melatonin directly into the bloodstream—bypassing the digestive system for faster results.

Key benefits:

• Fast-acting relief – Works in as little as 15–20 minutes by delivering melatonin straight into your system.
• Discreet and convenient – Slim, easy to use, and perfect for travel, jet lag, or shift work.
• Tailored strengths – Choose from a range of strengths from 2mg to 8.5mg to match your personal sleep needs

Melatonin FAQs

Can I take melatonin every night? 

While melatonin is safe for short-term use, nightly consumption over extended periods requires medical supervision.

Is melatonin addictive? 

No, melatonin is not considered addictive and does not cause dependency.

Can children take melatonin? 

Children can take melatonin under a doctor’s supervision, particularly for sleep disorders. However, long-term use may not be safe due to potential effects on hormonal development.

Can I take melatonin during pregnancy? 

Melatonin use during pregnancy is not well-studied, so consult your doctor before using it.

Are there natural ways to boost melatonin production? 

Yes, practices like maintaining a consistent sleep schedule, reducing screen time before bed, and creating a dark, quiet sleeping environment can naturally boost melatonin levels [11].

Conclusion

Melatonin is a popular and generally safe sleep aid when used appropriately. Its side effects are typically mild, but certain individuals should approach its use cautiously.

For more sleep health and wellness guidance, contact us for your FREE sleep consultation.

If you are concerned about insomnia and would like to speak to one of our specialists, please contact us for a FREE sleep health consultation.

Disclaimer: This article is for informational purposes only and does not replace professional medical advice.

References

1. Medical Mojo. (n.d.) What is melatonin? – Normal melatonin release. Available at: https://medicalmojo.co.uk/what-is-melatonin/#h-normal-melatonin-release (Accessed: 21 March 2025).
2. Besag, F.M., Vasey, M.J., Lao, K.S. and Wong, I.C., 2019. Adverse events associated with melatonin for the treatment of primary or secondary sleep disorders: a systematic review. CNS drugs, 33, pp.1167-1186.
3. Rishi, M.A., Khosla, S., Sullivan, S.S. and Public Safety and the Public Awareness Advisory Committees of the American Academy of Sleep Medicine, 2023. Health advisory: melatonin use in children. Journal of Clinical Sleep Medicine, 19(2), pp.415-415.
4. https://aasm.org/advocacy/position-statements/melatonin-use-in-children-and-adolescents-health-advisory/
5. Li J, Somers VK, Xu H, Lopez-Jimenez F, Covassin N. Trends in use of melatonin supplements among US adults, 1999-2018. JAMA. 2022;327(5):483–485.
6. Gummin DD, Mowry JB, Beuhler MC, et al. 2020 annual report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 38th annual report. Clin Toxicol (Phila) 2021;59:1282–501. 10.1080/15563650.2021.1989785 – DOI 
7. Minich, D.M., Henning, M., Darley, C., Fahoum, M., Schuler, C.B. and Frame, J., 2022. Is melatonin the “next vitamin D”?: a review of emerging science, clinical uses, safety, and dietary supplements. Nutrients, 14(19), p.3934.
8. Courier Pharmacy. (n.d.) Is it safe to take melatonin every night? Available at: https://courierpharmacy.co.uk/is-it-safe-to-take-melatonin-every-night/ (Accessed: 21 March 2025).
9. Medical Mojo. (n.d.) What is Quviviq? Available at: https://medicalmojo.co.uk/what-is-quviviq/ (Accessed: 21 March 2025).
10. Boafo, A., Greenham, S., Alenezi, S., Robillard, R., Pajer, K., Tavakoli, P. and De Koninck, J., 2019. Could long-term administration of melatonin to prepubertal children affect timing of puberty? A clinician’s perspective. Nature and science of sleep, pp.1-10.
11. Medical Mojo. (n.d.) Fifteen tips for healthy sleep. Available at: https://medicalmojo.co.uk/fifteen-tips-for-healthy-sleep/ (Accessed: 21 March 2025).

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