Melatonin Before Sunset, Not Before Bed

Melatonin is sleep-cycle related hormone. Part of getting sleepy is a spike of it as it gets dark (DLMO - Dim Light Melatonin Onset).

I’ve experimented with small doses (1mg) from 10 minutes to 2 hours before bed. I didn’t notice much difference except that I seemed to wake with dawn more readily. I’ve heard it’s not useful as a regular sleep aid, and should be reserved primarily for trying to move the onset of sleep earlier (e.g. for jet lag) by maybe 30-60 min.

A new study of high schoolers taking 1mg melatonin late in the afternoon gave teens a 1hr earlier bedtime and 1hr more of sleep, which naturally led to decreased sleepiness during school.

Given that bright blue light from LCD screens, like daylight, can delay sleep, I’m impressed that this pre-sunset dosing made a difference (the kids probably didn’t avoid using bright screens). The authors explain why they dosed in late afternoon instead of at night:

If melatonin is taken some hours before dim light melatonin onset (DLMO), it will advance the sleep timing (Lewy et al.,1998).

Both time and dose of melatonin administration determine its phase shifting effect. Given after DLMO, as is the case when it is used as a sleep aid, it has no or minimal such effect (Burgess et al., 2008)

I don’t recommend more than 1-2mg doses, and it’s easy to find 1mg melatonin pills. 1mg is already 3 times the amount you produce on your own, and large (10mg+) doses feel unpleasant.

Apparently some studies dose melatonin at 8pm, since the natural peak level occurs then. This study used 4:30-6pm.