How much

How much melatonin should older adults take?

By GyroscopeUpdated November 14, 20267 sources

Less than most bottles hold. In a trial of adults over 50, 0.3 mg restored sleep and brought blood levels back to a normal night, while 3 mg also helped but kept melatonin raised into the daylight hours. Start at 0.3 to 0.5 mg, 1 to 3 hours before bed.

Older people often sleep worse, and many have heard that their bodies make less melatonin, so a big dose sounds like the way to top it up. The MIT team that ran the trial started from that idea too. Their poor sleepers did have low night melatonin, and the dose that fixed it was tiny.

We’d start at 0.3 to 0.5 mg, take it 1 to 3 hours before bed, and give it two weeks. If you take a prescription medicine every day, ask your prescriber first.

It’s like topping up a car that’s a quarter low. You fill it to the top and stop, because anything more spills down the side.

The trial that set the dose

In 2001, researchers at MIT studied 30 adults over 50. Half slept normally, and half had poor sleep efficiency confirmed by a wrist tracker. Each took a placebo, 0.1, 0.3 and 3 mg, 30 minutes before bed, for a week each with a week off in between, and had their sleep recorded on the last three nights of each week.

0.3 mg restored sleep efficiency in the poor sleepers, mostly in the middle third of the night, and brought their blood melatonin up to normal. 3 mg also improved sleep, but it lowered body temperature and kept melatonin raised into daylight. The normal sleepers had low melatonin too, and no dose changed their sleep at all.

That last result is the surprise. Low melatonin by itself didn’t mean bad sleep, and topping it up only helped the people who were sleeping badly.

Why the slow end of the curve

The US National Center for Complementary and Integrative Health says melatonin may stay active longer in older people and cause daytime drowsiness. How fast people clear it varies a lot. In surgery patients, the half-life of a 10 mg tablet went from about 60 minutes before an operation to about 104 minutes the evening after.

Our night curve uses a slower 1.5 hour half-life for anyone 60 or over. On that band, 10 mg at 10:30pm is still above your own night’s peak at 6:30am, while 0.5 mg is long gone.

Say you’re 62

You wake at 6:30am on days with no alarm and go to bed around 10:30pm. Your own melatonin probably starts around 8:20pm. To fall asleep faster, take 0.3 to 0.5 mg between 7:30 and 9:30pm, and switch to lamps from then on. That estimate of when your melatonin starts came from young people, so for older adults it’s a rougher guide, and your own nights decide.

Staying asleep

If the trouble is waking in the night, a slow-release tablet may suit you better. In a 1995 trial in older adults with insomnia, 2 mg slow-release improved staying asleep, a regular tablet improved falling asleep, and two months on 1 mg slow-release kept working with no sign the effect was wearing off.

Who should skip it

The American Academy of Sleep Medicine’s 2015 guideline recommends against melatonin for older people with dementia. Melatonin also interacts with some medicines, including fluvoxamine, blood thinners and nifedipine, so ask your prescriber before you start. The medicines answer has the details, and loud snoring or stopped breathing is a reason to see a doctor before trying anything.

Turn on the 60 or over switch in the tool below to see your dose on the slow band. Don’t drive after a dose.