The short answer
Most melatonin starts to work in about 30 to 60 minutes. A regular dose reaches its peak in the blood in about 50 minutes, and your body clears half of it in about 45 minutes.1 So most of a low dose is gone within a few hours.
Bigger doses start much higher, so they can stay above normal into the next morning.2 That is why some people feel drowsy or foggy when they wake up. Slow release melatonin is different. It is built to keep working for many hours.4
A night with melatonin, hour by hour
Here is roughly what happens with a regular, fast release dose taken before bed.1,2
0 minutes
You take it. Melatonin is absorbed fairly fast, but only a small share of a swallowed dose reaches your blood.1
30 to 60 minutes
Levels rise and peak. This is when most people start to feel ready for sleep.1
About 1 to 2 hours
Your body has already cleared about half of it. Melatonin has a half life of about 45 minutes.1
About 4 to 5 hours
Most of a low dose is gone. By now, your body's own night signal should be doing the work.
Morning
With a low dose, levels are usually back to normal. With 3 mg or more, levels can still be high.2
Timing varies from person to person, and with the dose and the form you take.
Why it seems to work fast for some people and not at all for others
When I talk to friends and family who take melatonin, I hear every answer. Some say it works quickly. Some say they feel nothing. And some tell me they know it works because they wake up drowsy the next morning.
That last one is worth a second look. Waking up drowsy is not proof that melatonin is working well. It is often a sign that the dose was more than your body needed. In a study of adults over 50, 0.3 mg brought night levels back to normal, while 3 mg pushed levels far above normal and kept them high into the next day.2
It also helps to know what melatonin is. It is a time signal, not a sleeping pill. In a large review of studies, it helped people fall asleep about 7 minutes faster on average.3 That is a gentle nudge, not a knockout. If you expect to be knocked out, it can feel like it did nothing. If you expect a calm signal that night has started, it makes more sense.
Other things change how fast you feel it:
- Light. Bright light in the evening lowers your own melatonin and pushes your body clock later.5 Taking melatonin while scrolling on your phone works against it.
- The dose on the label. Many products do not hold what the label says. In one test, 22 of 25 melatonin gummies did not match their labels.6
- Age. Your body makes less melatonin as you get older.9
How long does melatonin last by dose?
| Dose and type | How long it lasts |
|---|---|
| 0.3 to 1 mg, fast release | Peaks in about an hour, mostly cleared within a few hours. 0.3 mg kept levels in the normal night range in adults over 50.1,2 |
| 3 mg, fast release | Raised levels far above normal and kept them high into the next day in adults over 50.2 |
| 5 to 10 mg, fast release | Starts even higher, so it takes longer to clear. More likely to leave you groggy.2,7 |
| 2 mg slow release | A prescription form in Europe for adults 55 and older, made to release melatonin over many hours.4 |
On a phone, swipe the table sideways to see every column.
For more on low doses, read is 1 mg of melatonin enough.
Does melatonin wear off at 3am?
Many friends and family members have told me they woke up in the middle of the night after taking melatonin, and then woke up in the morning still drowsy, feeling like a zombie and in a funk all day. But I am not sure the melatonin was the reason they woke up. Melatonin often gets the blame because it is the ingredient people know, when there are many other reasons a night can fall apart.
Here is what we know. Fast release melatonin is mostly cleared within a few hours.1 That is why a slow release form exists for people whose main problem is staying asleep.4 So it is true that a fast release dose is not still working at 3am.
But that does not mean it caused the wake up. For adults over 40, common reasons for 3am waking include:
- Night sweats and hot flashes
- Alcohol earlier in the evening
- A full bladder
- Stress and a racing mind
- Lighter sleep later in the night, which is normal with age
I go through these one by one in why you keep waking up at 3am. One thing I always say: do not take a second dose in the middle of the night. It can still be working when your alarm goes off, which is a recipe for a foggy morning. Read more in why you feel groggy after melatonin.
When should you take melatonin?
I tell people to take melatonin about 30 minutes to an hour before bed, because it absorbs quickly. Just as important, take it at the same time every night. If you go to bed at 10pm, take it around 9:00 to 9:30, and make it part of a calm routine, like reading a book or lying in a dim room and relaxing.
| If your bedtime is | Take melatonin around |
|---|---|
| 9:30pm | 8:30 to 9:00pm |
| 10:00pm | 9:00 to 9:30pm |
| 10:30pm | 9:30 to 10:00pm |
| 11:00pm | 10:00 to 10:30pm |
The 30 minute timing matches how melatonin was given in the MIT study of adults over 50.2 Follow your product's label, and ask your doctor if your sleep schedule is unusual, such as shift work.
The routine matters as much as the timing
Melatonin tells your body that night has started. Dim lights, a book, and the same bedtime send that same message. When they all line up at the same time every night, the signal gets stronger.5
Where Driffly fits
A low dose that fits a bedtime routine
I chose 1 mg for Driffly so the dose stays in the low range and is less likely to linger into the morning than 5 mg or 10 mg.2 It is the same amount behind the European Union's approved melatonin sleep claim.8 You take one strip about 30 minutes before bed, at the same time each night.*
- 1 mg of melatonin in each strip.
- Valerian root, lavender, chamomile, and hibiscus to support a calm wind down.*
- Melts on your tongue. No water and no sugar.
Every order comes with a 30 night money back guarantee.
Common questions about how long melatonin lasts
How long does melatonin take to kick in?
Usually 30 to 60 minutes. A regular dose peaks in the blood in about 50 minutes.1
How long does 1 mg of melatonin last?
With a half life of about 45 minutes, most of a 1 mg fast release dose is cleared within a few hours.1 Low doses are less likely to stay high into the morning than larger ones.2
How long does 5 mg or 10 mg of melatonin last?
Larger doses start much higher, so they take longer to clear. Even 3 mg kept levels above normal into the next day in adults over 50.2
Why do I still feel melatonin in the morning?
Usually the dose was more than your body needed, or you took it late at night. Try a lower dose taken earlier, at the same time each night.2
Can I take another dose if I wake up at 3am?
It is better not to. A second dose can still be working when your alarm goes off. Talk to your doctor if you wake up most nights.
Is it safe to drive after taking melatonin?
Do not drive or use machines for several hours after taking melatonin, because it can cause drowsiness.7 If you feel drowsy in the morning, wait until you feel fully alert.
Sources
- Harpsoe NG, Andersen LP, Gogenur I, Rosenberg J. Clinical pharmacokinetics of melatonin: a systematic review. European Journal of Clinical Pharmacology. 2015;71:901-909.
- Zhdanova IV, Wurtman RJ, Regan MM, et al. Melatonin treatment for age-related insomnia. The Journal of Clinical Endocrinology and Metabolism. 2001;86(10):4727-4730.
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.
- European Medicines Agency. Circadin (melatonin 2 mg prolonged-release tablets): product information.
- Gooley JJ, Chamberlain K, Smith KA, et al. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. The Journal of Clinical Endocrinology and Metabolism. 2011;96(3):E463-E472.
- Cohen PA, Avula B, Wang YH, Katragunta K, Khan I. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA. 2023.
- Mayo Clinic. Melatonin side effects: What are the risks? Expert Answers, Adult Health.
- European Commission. Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (melatonin: reduction of time taken to fall asleep, at least 1 mg per portion). 2012.
- Karasek M. Melatonin, human aging, and age-related diseases. Experimental Gerontology. 2004.
Tyler Smith, RN, BSN, BA is a registered nurse and the founder of Driffly. He writes and reviews the articles in the sleep education hub. About Tyler
The author is the founder of Driffly, which sells the product mentioned in this article. This article is for education and is not medical advice. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.