How much melatonin should you take, and when?
Melatonin is one of the few supplements where when you take it matters more than how much. This free calculator gives you a clock time and a starting dose for falling asleep, jet lag, shift work, or pulling a very late sleep schedule earlier — with the label's own safety rules built in.
Take it at
9:00 PM about 90 minutes before your target sleep time
Each tablet also contains 10 mg of vitamin B-6.
Educational estimate only, not medical advice. Melatonin is a hormone, not a vitamin — talk to a doctor or pharmacist before using it, especially alongside any medication.
Most people treat melatonin like a sleeping pill: swallow it in bed, wait to feel drowsy. That is the wrong model. Melatonin is the signal your brain uses to mark the start of biological night, so its job is to tell your body clock what time it is. Take it at the wrong hour and it can shift your clock in the direction you did not want.
Quick answer: For simple trouble falling asleep, take 1 to 3 mg of melatonin about 1 to 2 hours before your target bedtime. Lower doses generally work as well as higher ones and leave less morning grogginess. For jet lag, take it at bedtime in your destination time zone. To pull a very late sleep schedule earlier, a low dose 3 to 4 hours before your desired sleep time is the usual approach.
Key Takeaways
- Timing beats dose. 1 to 3 mg taken two hours before bed is the standard starting point.
- More is not better — higher doses mainly add next-day grogginess.
- Tablets can be split, so a 3 mg tablet gives you a 1.5 mg starting dose.
- Bright light after your dose cancels much of the effect. Dim the room.
- Melatonin helps circadian problems like jet lag more than it helps chronic insomnia.
- The label rules out under-18s and several health conditions. Check them before buying.
How the calculator works
The dose side is deliberately conservative. Sleep medicine guidance converges on 1 to 3 mg taken roughly two hours before bedtime, with the explicit advice that less is more.[1]Melatonin for Sleep: Does It Work? — Johns Hopkins Medicine View source The tool only steps you up to 5 or 10 mg if you tell it a lower dose already did nothing, and it steps you back down if melatonin has left you groggy.
The timing side changes with what you are trying to fix. For ordinary sleep-onset trouble the window is 1 to 2 hours before bed.[2]George S. et al. Melatonin dose and timing: Do we have it right? (2025) — PMC13064696 View source If your body clock is genuinely running late and you want to shift it earlier, the dose goes earlier still, several hours ahead of your target sleep time. For jet lag, the anchor is bedtime in the place you are going, not the place you left.
| What you are fixing | When to take it | Typical dose | How long |
|---|---|---|---|
| Trouble falling asleep | 1–2 hours before target bedtime | 1–3 mg | A few nights at a time |
| Body clock running late | 3–4 hours before target sleep time | 0.5–3 mg | Until the schedule holds |
| Jet lag | At bedtime in the destination zone | 1–3 mg | About 1 night per zone crossed |
| Shift work | 1–2 hours before your daytime sleep | 1–3 mg | Through the run of shifts |
Melatonin has the strongest evidence for circadian problems such as jet lag and delayed sleep phase. It is not a first-line treatment for chronic insomnia, and clinical bodies do not recommend it for that use.[3]Melatonin — Mayo Clinic drugs and supplements View source
Why the light in the room matters as much as the dose
Melatonin works by signalling darkness. Bright light, and blue-heavy screen light in particular, suppresses your own melatonin and blunts the supplement you just took. Taking 5 mg and then scrolling in a brightly lit room is close to self-cancelling.
The practical version: after you take your dose, drop the lights, keep screens dim or away, and let the next hour be genuinely dark. That single habit does more than doubling the milligrams.
Going deeper on melatonin
This calculator gives you a starting point. For the full picture — how melatonin actually works, what it does and does not treat, and how it compares to other sleep aids — read our complete guide to melatonin supplements.
If you want the timing detail behind this tool, when to take melatonin: timing for sleep, jet lag and shift work covers each scenario in depth. And before you settle on a number, melatonin dosage: how much should you take explains why the lowest effective dose is the goal.
Melatonin — 3 mg, 5 mg and 10 mg Vegan Tablets
Three strengths so you can start low and only step up if you need to. Each tablet also supplies 10 mg of vitamin B-6. Tablets are splittable, so the 3 mg gives you a 1.5 mg starting dose. Made in the USA, no fillers.
Shop Melatonin →Frequently Asked Questions
When should I take melatonin? +
For ordinary trouble falling asleep, take it 1 to 2 hours before the time you want to be asleep, not once you are already in bed. If you are trying to move a late body clock earlier, take a low dose 3 to 4 hours before your target sleep time instead.
How long does melatonin take to kick in? +
Blood levels peak roughly 30 to 60 minutes after an immediate-release tablet, and most people notice drowsiness somewhere in that window. That is exactly why taking it in bed is too late, and why the standard advice is 1 to 2 hours ahead.
Can I take melatonin and go straight to sleep? +
You can lie down, but do not expect it to work like a sedative. Melatonin signals that biological night has started rather than knocking you out. Give it an hour of dim light before your target sleep time and it works with your clock instead of against it.
Is it OK to take melatonin every night? +
Short-term nightly use is generally considered safe, but melatonin is best used in bursts to reset a schedule rather than indefinitely. Long-term nightly use has not been well studied. If you need it every night for months, the underlying sleep problem deserves a proper look.
What time is too late to take melatonin? +
As a rule, if you have fewer than 7 to 8 hours before you must be up, taking it risks morning grogginess. Taking melatonin in the small hours can also shift your clock later, making tomorrow night worse. If you wake at 3am, it is usually better to skip it.
Can I take melatonin at 3am? +
It is generally a bad idea. At that hour you rarely have a full sleep window left, so you wake groggy, and a dose that late can push your body clock further in the wrong direction. Getting up briefly in dim light and returning to bed is usually the better move.
How much melatonin should an adult take? +
Start at 1 to 3 mg. Studies repeatedly find that low doses work about as well as high ones, while high doses add side effects such as morning grogginess and vivid dreams. Only step up if a low dose genuinely did nothing over several nights.
Is it safe to take 10 mg of melatonin every night? +
10 mg is far above the amount most people need, and there is no good evidence it outperforms 1 to 3 mg for sleep onset. It mainly increases the chance of grogginess, headache, and vivid dreams. If 10 mg is the only dose that seems to help, that is a reason to see a doctor.
What happens if you take melatonin and do not go to sleep? +
Usually nothing dramatic. You may feel drowsy and slightly cool, and that feeling fades over a couple of hours. The bigger cost is that staying in bright light after your dose wastes it, and being awake through the window can nudge your clock in the wrong direction.
Is there a downside to taking melatonin? +
The common ones are next-morning grogginess, headache, dizziness, nausea, and unusually vivid dreams, and they get more likely as the dose rises. It also interacts with several medication classes. It is a hormone, so it deserves more caution than a typical vitamin.
How do I use melatonin for jet lag? +
Anchor it to bedtime in your destination time zone and take 1 to 3 mg then, for roughly one night per time zone you crossed. It helps most flying eastward, where you need to fall asleep earlier than your body wants. Morning daylight at the destination does the other half of the work.
Does melatonin help with shift work? +
It can help you fall asleep during the day after a night shift if you take it 1 to 2 hours before your sleep period and sleep in a properly darkened room. It does not make you alert on shift, and it should never be taken before driving home.
Why does this melatonin contain vitamin B-6? +
Vitamin B-6 is a cofactor in the pathway your body uses to make its own melatonin from tryptophan, which is why it is a common pairing. Each tablet supplies 10 mg. Worth knowing if you already take a B-complex, so you can keep an eye on your total.
Who should not take melatonin? +
The product label states it is not for anyone under 18, and not to be taken by people with an autoimmune disease, depression, diabetes, an endocrine disorder, or a thyroid condition. Anyone pregnant, breastfeeding, or taking prescription medication should clear it with a clinician first.
Looking for a different number? See all free supplement calculators.
Medical Disclaimer
This calculator provides general educational estimates only and is not medical advice, a diagnosis, or a treatment plan. Melatonin is a hormone, and the right dose and timing depend on your circadian rhythm, medications, and health history.
The product label states this supplement should not be used by:
- anyone under 18 years of age;
- people with an autoimmune disease, diabetes, an endocrine disorder, or a thyroid condition;
- people with depression or another mental health condition;
- anyone operating a motorized vehicle or heavy machinery.
If you are pregnant, breastfeeding, or taking any prescription drug — including blood thinners, blood pressure or diabetes medication, anticonvulsants, or sedatives — consult a health care professional before use. Use only at bedtime. Persistent sleep problems lasting more than a few weeks should be assessed by a doctor rather than managed with a supplement.
These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.