Taking melatonin supplements does not appear to help reduce the frequency or intensity of sleep-related acting out behaviors in people who have Parkinson's disease. If you or a loved one has this condition, melatonin is unlikely to make the dream-enacting symptoms like sleepwalking or talking during sleep any better.

Taking melatonin doesn't change most sleep measurements for people with Parkinson's disease, but it might help them fall asleep faster and sleep for a longer total time. It doesn't, however, change the deeper stages or structure of their sleep.

Taking melatonin might make sleep scores look slightly better on paper for Parkinson's patients, but the actual improvement is too small to make a real difference in how they feel or function day-to-day.

Taking melatonin helps people with Parkinson's disease sleep better and feel less sleepy during the day. It reduces their insomnia symptoms and helps them feel more rested compared to not taking it.