Trips, shifts and late nights

Why isn't melatonin working for me?

By GyroscopeUpdated November 14, 20268 sources

Usually it’s the hour, the light, or the job you’re asking it to do. On average melatonin gets people to sleep about 7 minutes faster, and 5.5 minutes when it’s measured in a sleep lab or with a wrist tracker. If you take it at lights out in a bright room, you may not notice anything at all.

It’s easy to expect melatonin to knock you out like a sleeping pill, and to take more when it doesn’t. But melatonin’s main job is telling your body clock it’s evening, so the hour and the light around it decide most of what it does, and doubling the dose mostly adds grogginess in the morning.

We’d change the hour first. Take 0.5 to 1 mg one to three hours before bed, switch to lamps, and skip it on drinking nights. Then run a two-week test and let your own nights decide.

It’s like an alarm clock set for the wrong time. The alarm works, but it goes off when you’re already in bed.

The usual reasons, in order

1. The hour. A 2024 analysis of 26 trials found that the longer the gap between the dose and sleep, the more it helped people fall asleep, and the authors suggested about 3 hours before bed. At lights out, the tablet is still climbing to its peak while you lie there.
2. The light. In a 2011 study, ordinary room light in the hours before bed made melatonin start later in 99 percent of 116 young adults. A tablet in a bright room is working against the lights.
3. The job. Melatonin helps you fall asleep and moves your clock. It’s not built to keep you asleep through the night, and the American Academy of Sleep Medicine’s 2017 guideline suggests doctors don’t use it for long-term insomnia in adults.
4. Drinks. In a 2007 lab study, a moderate evening drink cut young adults’ own melatonin by 15 to 19 percent over the next few hours.
5. The bottle. In a 2023 test of 25 US melatonin gummy products, one had no melatonin, and the rest held 74 to 347 percent of the label.
6. Something else is waking you. Loud snoring or stopped breathing can be a sign of sleep apnea, and melatonin doesn’t treat it. See a doctor about it first.

How big an effect to expect

In a 2013 analysis of 19 trials with 1,683 people, melatonin cut 7 minutes off the time to fall asleep and added about 8 minutes of sleep. Measured with sleep lab equipment or a wrist tracker, the time to fall asleep dropped 5.5 minutes. By people’s own reports it was nearly 11 minutes, about twice what the equipment measured. The effect was modest, but it didn’t fade with use, and longer trials found bigger effects.

What about your phone?

The room seems to do more than the screen. In a small 2016 study, 14 people spent the day in bright light, then spent 2 hours on a tablet or with a printed book before bed, and their sleep and melatonin came out the same. Taken together with the room light study, that points at the overhead lights more than the phone.

Your own two weeks

Say your off nights take 25, 18, 32, 22, 40, 20 and 28 minutes to fall asleep, a median of 25, with a normal swing of about 8 minutes. Your on nights take 20, 15, 24, 19, 22 and 17, a median of 19.5, with one drinks night left out. That’s 5.5 minutes faster, inside your normal swing, and about the size the trials found. The verdict is “Inside your normal swing”, which is the cue to try the right hour before giving up.

The tool below does this math for your nights. Insomnia that lasts more than a few weeks is a reason to see a doctor, and the American College of Physicians recommends cognitive behavioral therapy for insomnia (CBT-I) as the first treatment. Don’t drive after a dose.