Melatonin alleviates jet lag symptoms caused by an 11‐hour eastward flight

The effect of 3 mg of melatonin on the rate of re‐entrainment of plasma melatonin rhythm after an 11‐h eastward flight was assessed. Eight subjects participated in the study, and underwent 24‐h blood samplings once before the flight and twice after the flight. Subjects were exposed to natural zeitgeber outdoors and took 3 mg of malatonin at 20:00 h local time on the days when no blood sampling was done. Antidromic re‐entrainment was dominant whereby melatonin administration in the evening promoted re‐entrainment. Melatonin accelerated the rate of re‐entrainment by 15 min per day and alleviated the jet lag symptoms.