Is Melatonin Safe for Everyone?

Published on: 12/05/2022
An Overview of Melatonin

When I used to work primarily with older people, one of the most common complaints I heard was poor sleep. Unfortunately, medications for insomnia are notoriously risky for seniors. They increase the risk of falls, fractures, and cognitive impairment. As a result, there weren’t many pharmaceutical options that could be offered. We would often default to the supplement melatonin, since it had the reputation of being safe and effective.

But was it really?

Let’s look more closely at what melatonin is, what it’s useful for, and how safe it is.

Melatonin – Not Just a Sleep Hormone

Melatonin is a hormone naturally produced by the pineal gland in the brain which promotes sleep and governs the body’s circadian rhythm. It is created from the amino acid, tryptophan, which might be one of the reasons why it’s said that eating turkey causes sleepiness. (1)

The production of melatonin is controlled by light. Levels rise with darkness, leading to sleepiness, and fall with light, causing wakefulness. This is why sleep experts will tell you to use blue-blocking glasses at night and turn off your devices at bedtime, as artificial light can disrupt the normal pattern of melatonin production and cause insomnia.

Interestingly, even though melatonin is most famous for its effects on sleep, even more is produced by enterochromaffin cells in the intestines. Here it promotes gastrointestinal (GI) motility, promotes the growth of beneficial gut bacteria, and modulates the release of stomach acid. (2)

It is also found in small amounts within many other tissues throughout the body. Melatonin is an important antioxidant, anti-inflammatory, and immune enhancing compound. It protects tissues and organs against damage and keeps mitochondria (3) healthy. (2,4)

Melatonin is an important antioxidant, anti-inflammatory and immune enhancing compound.

Clinical Uses

Given its myriad of functions, there is much interest in using melatonin for a variety of purposes.

Here are just a few evidence-based uses for melatonin: (2,4,5)

  • Supports sleep in shift-workers
  • Hastens recovery from jet lag
  • Helps with circadian rhythm sleep disorders
  • Improves insomnia (including cases related to older age, certain medications, depression, autism, and traumatic brain injury)
  • Reduces endometriosis pain
  • Prevention of migraines
  • Protection of the GI tract from damage due to NSAIDs and heavy metals (6)
  • Relief of anxiety related to medical procedures

As with any drug or supplement, there is always a possibility of side effects and interactions. Please check with your doctor or pharmacist before taking melatonin, particularly if you have medical conditions or are taking medications that are also metabolized through the liver enzymes CYP1A2 and CYP2C19.(7)

In general, short-term use of melatonin appears to be quite safe, even at higher doses of 10mg or more. The usual recommended dose for insomnia is between 0.3-5mg at bedtime. It has also been used safely in children, though lower doses are advised. Unfortunately, there isn’t sufficient data to confirm the safety of long-term use of melatonin (i.e. 6 months or more) or in people who are pregnant or breast-feeding, so this is best avoided.(5,7)

Reported side effects are few and tend to be mild. The most common are nausea, dizziness, headache, and sleepiness. (7) It would be smart to avoid or at least use melatonin with caution if driving or operating dangerous machinery. Older adults or people with balance issues may be at higher risk of falling. Of note, the controlled-release formulas have longer lasting effects and could cause a “hang-over” the next day.

The Bottom Line
  • Melatonin is a safe and effective supplement for insomnia, sleep difficulties related to disturbances in circadian rhythms, and a variety of other conditions.
  • Side effects are generally mild, but use should be limited to a short period of time
  • Use with caution if alertness is required, or if at higher risk of falling.
  • There are potential interactions which necessitate consultation with a physician or pharmacist.

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Endnotes and References

1. Okay, okay – the bigger reason is probably the blood sugar crash from eating all the lovely sides that usually go along with turkey. But presumably, at least some of the tryptophan in turkey will eventually make its way into melatonin.

2. (Pal et al. 2019. Enterochromaffin cells as the source of melatonin: key findings and functional relevance in mammals.)

3. Mitochondria are organelles found within virtually every cell in the body which are responsible for creating energy. Unfortunately, they produce lots of damaging free radicals during this process, which requires the concerted effort of many antioxidant compounds, including melatonin.

4. (Minich et al. 2022. Is melatonin the next vitamin D? A Review of Emerging Science, Clinical Uses, Safety, and Dietary Supplements)

5. Natural Medicines On-Line Database. Melatonin monograph, last updated 10/13/2022. Accessed Dec 3, 2022 from

6. NSAIDS = non-steroidal antiinflammatory drugs, such as ibuprofen, aspirin, and naproxen; melatonin has been found to protect against damage from the heavy metals cadmium, mercury, lead, and arsenic. (2)

7. (Andersen et al. 2015. The safety of melatonin in humans.)

The information contained in this article is intended for educational and entertainment purposes only. It is not to be construed as personalized nutritional advice nor intended to be a substitute for proper health and medical care. Please consult your physician or a qualified health care professional for support with your insomnia or other health needs.


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Hi! I’m Dora – an unconventional pharmacist turned functional medicine nutritionist. I’m also a mom of twins and an autoimmune warrior.

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