Melatonin appears to be safe for everyday use, especially on a short-term basis. Daily melatonin use long term has not been studied, so the long-term effects on safety are unknown. To best mimic your body’s natural sleep-wake cycle, you should take melatonin at the same time each night as part of a nightly routine.Melatonin appears to be safe for everyday use, especially on a short-term basis. Daily melatonin use long term has not been studied, so the long-term effects on safety are unknown. To best mimic your body’s natural sleep-wake cycle, you should take melatonin at the same time each night as part of a nightly routine.