When to take it

Can I take melatonin in the middle of the night?

By GyroscopeUpdated November 14, 20266 sources

Only a small dose, and only with 5 or more hours left before you get up. A tablet peaks about 40 minutes after you take it and then halves about every hour. On our model 0.5 mg at 3am is back to a normal night’s level by about 4:20 to 4:45am, while 3 mg stays above it until about 6:40 to 8:40am.

Waking at 3am feels like a sleep problem, so reaching for the sleep aid on the nightstand seems obvious. But a dose that would have been gone by morning at 10pm is still running when the alarm goes off if you take it at 3am, and the groggy morning that follows comes from the dose still in your blood.

For 3am waking we’d look for the cause first. The usual ones are drinks in the evening, a bright bathroom light, and loud snoring or pauses in breathing. If you still want something, take 0.5 mg, and only if you have at least 5 hours left in bed.

It’s like eating a full dinner at 3am. The food is fine, but you’ll still be digesting it when you sit down for breakfast.

How long a dose at 3am lasts

The range runs from the measured half-life of about 54 minutes to a slower 1.5 hours, for people who clear it slowly.

The speed is from a 2016 Copenhagen study in which 12 men swallowed 10 mg, peaked at about 40 minutes and lost half every 54 minutes. The height scales with the dose, and 0.3 mg gives about a normal night’s peak. In adults over 50, even 3 mg taken at bedtime kept melatonin raised into the daylight hours, and a 3am dose has 4 or 5 fewer hours to clear.

Why your bedtime dose didn’t keep you asleep

A regular tablet at bedtime is mostly gone by 3am. Taken at 10:30pm, 0.5 mg is back under your own level by about midnight and 3 mg by somewhere between 2:10 and 4:10am. Regular melatonin is built for falling asleep. In a 1995 trial in older adults with insomnia, 2 mg slow-release helped them stay asleep, while the same dose as a regular tablet helped them fall asleep, and the slow-release answer covers when that’s the better choice.

The three things to check first

• Drinks. In a 2007 lab study, a moderate dose of vodka finished an hour before bed cut young adults’ own melatonin by 15 to 19 percent over the next few hours. Alcohol and melatonin has the rest.
• The bathroom light. In a 2011 study, ordinary room light during the usual hours of sleep cut melatonin by more than half in 85 percent of the tests. Use a dim night light, and keep the overhead light off.
• Your breathing. Loud snoring or stopped breathing can be a sign of sleep apnea, and melatonin doesn’t treat it. See a doctor about it first.

In the jet lag trials, melatonin taken early in the day made travelers sleepy and slowed their adjustment to the new time zone, so don’t top up again at 6am.

Try a dose at 3am in the tool below and set your alarm to see what’s left. Don’t drive after a dose.