It has no connection with the controversial hormone melatonin. This is a controversial and complex treatment for shift lag. This means the dosage is important and if not taken correctly could make the shift lag worse instead of better. The fact that it has been taken off the open market in Europe, Canada and Australia indicates concerns about its side affects. A full description of melatonin effects is available from this link.
Some shift workers use sleeping pills to try to alleviate shift lag.
They do have a down side. The shift worker can become addicted to them. Its true they increase the amount of sleep but they don't fix the problem of shift lag or increase the alertness of workers during the next shift. Bright Light Therapy Bright light boxes which deliver strong light are used by some to reset their time clock and once we now more about light therapy it may be used in night work situations. Some shift workers find when they are finishing a series of night shifts and are about to go back day shifts spending as much time outside in bright sunshine helps.