Everyone is familiar with the dreaded jet lag, that groggy feeling you can get for days after a long flight as your body adjusts to its new time zone. And everyone also has their own home remedies. But which remedies really work?

First, a bit of background: jet lag is caused by your body’s slow ability to adjust to the change in sunlight. Eastbound travel is worse than westbound, as your body has more trouble shortening its cycle. Your body usually readjusts only 1 hour per day in eastward travel, versus 1.5 hours per day traveling west. Your natural sleep (“circadian”) rhythm is controlled directly by the hormones melatonin and cortisol — and these are directly controlled by sunlight hitting your eyes. It’s all about sunlight, and the key to aiding jet lag is controlling that sunlight or adjusting the hormones.

With light exposure: westward travelers should stay awake and get as much daytime sun as possible, then sleep when dark; eastward travelers should also try not to nap but should avoid morning sun and get a lot of afternoon sun. Go sightseeing!

Eating: Try to eat at your new timezone as you usually would (i.e. keep your lunch at the new noontime).

Pills: The pill form of your natural hormone melatonin does have a fair bit of evidence that taking it can speed up your sleep adjustment — not by a huge amount, but enough to experiment with if you are a frequent flyer. The trick is the timing: Eastward travelers during flight should take it 30 minutes before your new bedtime, and then 30 minutes before bedtime each night in your new timezone. Westward travelers do not need melatonin during the flight, and should take it 30 minutes before bedtime each night in your new timezone. As for dosing, the usual 3mg dose is fine.

Other medicines such as sleeping pills; natural agents like valerian or chamomile, or 50mg Benadryl can help a bit but should be considered as secondary to sunlight and melatonin.

What doesn’t work? Alcohol can make jet lag even worse; and caffeine may keep you awake just when you’re supposed to fall asleep.

I’m curious, what do other people do? You can leave comments below. I take an OTC herbal/melatonin mixture from the US called SleepMD, plus 50mg Benadryl (“diphenhydramine”) and that works ok for me.