Melatonin 101 - Dosing, Timing, and What to Do When Melatonin Isn't Working

February 15, 2022

More Americans are using melatonin for sleep than ever before, but is this supplement actually safe or effective? This post covers how melatonin works, considerations for use, and alternatives to help you make an informed decision and get some ZZZs. 

Disclaimer: Consult your medical provider if you are considering starting any dietary supplement, including melatonin. This article is for informational purposes and does not constitute medical advice.

Alarm clock

What is melatonin?

Melatonin is a key hormone that is involved in your sleep-wake cycle, also known as your circadian rhythm. Your brain naturally ramps up melatonin production in response to darkness, which promotes sleep. Melatonin levels start to naturally decrease in the morning.

Supplemental melatonin is typically made synthetically and can be purchased over the counter in tablets, sprays, liquid tinctures, and even gummy form. 

Who is melatonin for?

Melatonin has been shown to be an effective sleep aid when taken on a short-term basis and is well-tolerated by most people. Research on melatonin as a sleep aid shows modest benefits, including falling asleep faster and a small increase in total sleep time. There is some evidence to suggest that melatonin can be helpful for shift workers, people with sleep-wake phase disorder, or those struggling with jet lag.

It is important to note that these benefits can vary based on individual responses to melatonin, which can be influenced by age, dose, timing, and existing sleep patterns. 

Per Cafer’s psychopharmacology:

  • Melatonin is not an FDA approved treatment for any condition
  • Melatonin is possibly effective for insomnia, jet lag, neuroprotection, stimulation of the immune system, and headaches
  • There is no clear evidence on melatonin and sundowning/delirium or manic episodes

Who is melatonin NOT for?

Since melatonin is a naturally occurring hormone, it should be safe to consume it in supplement form, right? Unfortunately, natural does not always mean safe. 

Taking too much melatonin can cause mild side effects like headache, nausea, and dizziness.

You should avoid or use caution when taking melatonin if you:

  • Are taking certain medications, including antidepressants, benzodiazepines, prescription sleep aids, anti-seizure drugs, immunosuppressants, oral contraceptives, and blood thinners 
  • Struggle with chronic insomnia: There is not enough evidence to conclude that long-term melatonin use is the most safe and effective solution for chronic insomnia.
  • Are pregnant or breastfeeding: Researchers do not have enough evidence to say if melatonin is safe for these populations.
  • Are an older adult (55 years or older):  Melatonin levels decline as you age, so older people may be more sensitive to melatonin supplements. You may require a smaller dose and notice that melatonin’s effects last longer.
  • Have dementia: Melatonin is not recommended for this group according to the 2015 American Academy of Sleep guidelines.
  • Are drinking alcohol: Since alcohol disrupts your melatonin levels and the way supplemental melatonin works in your body, it is best to avoid mixing melatonin and alcohol. 

Can you get addicted to melatonin? 

Melatonin is not considered habit-forming and some research suggests that its effects on sleep do not change over time. In other words, you don’t need to increase your melatonin dose over time to get the same sleep benefits.

Is melatonin safe?

The actual amount of active ingredients in dietary supplements like melatonin can also be higher or lower than what’s listed on the label, as these products are not regulated by the US Food and Drug Administration (FDA).

Woman sleeping using melatonin

Melatonin dosing

The amount of melatonin in over the counter supplements can vary widely. Standard doses range are typically 3 mg, 5 mg, and 10 mg, but some supplements are sold in higher or lower doses.

There are no universally accepted safe ranges for melatonin dosing.

After checking with your medical provider that it’s safe for you to take melatonin, start with the smallest dose possible (3 mg is typically recommended) and gradually increase your dose as needed until you find the right amount for you. 12 mg is considered the maximum daily dose. You can cut tablets into smaller doses (half or even quarters) to help you fine-tune your melatonin dose.

Melatonin timing

You may be wondering, how long does melatonin stay in your system? For most people, the effects of melatonin set in after 30-60 minutes and last 4-8 hours, depending on the dose. Melatonin supplements work best for sleep when given 3-5 hours before your bedtime

Keep in mind, melatonin’s effects can also vary based on your age, weight, lifestyle, and whether you take certain medications or consume caffeine. It may take up to two weeks for the melatonin to work.

Melatonin not working? Here’s what could be going on.

If you’re taking melatonin at a fairly high dose and still having trouble sleeping, you may be tempted to up your dose, but this may not be helpful or safe.

Consult with your medical provider to rule out other issues that could be interfering with your sleep. Chronic insomnia may require additional treatment, such as cognitive behavioral therapy or prescription sleep aids.


Melatonin is naturally found in certain foods, so adding these to your evening meal or snack can be a worthwhile alternative to over-the-counter melatonin supplements. Melatonin-rich foods include:

  • Cherries
  • Nuts
  • Eggs
  • Milk and other dairy products
  • Fish

Cherries high in melatonin

If you’re struggling with insomnia, first-line treatments often include behavioral changes such as improving your sleep hygiene, working on relaxation techniques, or CBT-based approaches.

When behavioral or nutritional approaches aren’t helping with your sleep, your medical provider may suggest a supplement like melatonin or a prescription sleep aid. 

Reviewed by: Kathy Hunter, PMHNP-BC

Chelsea Jackle, MFN, RDN, LD picture

Chelsea Jackle, MFN, RDN, LD

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