Prepare before the flight: Take 5 mg of melatonin, wake up earlier, and get bright light exposure. Day of the flight: take 5 mg of melatonin at 6 p.m. After the flight: take 5 mg at bedtime until adapted, and get 30 minutes of outdoor exercise to help speed up the process.

For managing jet lag on a plane, medical consensus in 2026 suggests a dosage of 0.5 mg to 3 mg of melatonin, taken approximately 30 to 60 minutes before your desired bedtime at your destination's time zone. It is a common mistake to take too much; studies show that higher doses (like 5 mg or 10 mg) do not necessarily help you sleep better but can increase the risk of vivid nightmares, grogginess, and "melatonin hangovers" upon landing. For eastward travel (where you lose time), taking a low dose on the plane during the flight's "night" period can help shift your internal clock. For westward travel, melatonin is often more effective once you have actually arrived at your destination to help you stay asleep. You should always test melatonin at home before your flight to see how your body reacts, and avoid combining it with alcohol or other sleep aids. Because melatonin is a hormone and not a traditional sedative, its goal is to signal "nighttime" to your brain, not to knock you out immediately like a sleeping pill.