Melatonin tablets contain the active substance melatonin. Melatonin tablets can be used for treatment of jet-lag in adults. Jet-lag can be recognized by sleep disturbances, daytime tiredness, fatigue, mild mental impairment, irritability and digestive system disturbances experienced after flying.Studies have shown that 0.5 mg to 3 mg doses of melatonin are adequate to help in falling asleep and staying asleep. Always check with a healthcare provider before giving melatonin supplements to children, adolescents, and older adults.What are the health benefits of taking melatonin? Melatonin supplements may help with certain conditions, such as jet lag, delayed sleep-wake phase disorder, some sleep disorders in children, and anxiety before and after surgery.