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 travelers using melatonin to combat jet lag on long-haul flights, the recommended dosage is typically between 0.5 mg and 3 mg. Medical professionals often suggests starting with a lower dose (around 0.5 mg to 1 mg) to see how your body reacts, as higher doses can sometimes lead to vivid dreams, grogginess, or headaches. The timing is just as important as the dose: you should take it close to the local bedtime of your destination once you arrive, or during the flight if you are trying to sync your internal clock to a night-time arrival. Standard tablets are usually 3 mg, while slow-release versions are often 2 mg. It is important to consult with a doctor before starting melatonin, especially if you are on other medications or have underlying health conditions, and to avoid using it for more than a few days consecutively.