Harvard University, May 19, 2022
In a small study of healthy adults aged 55 and older, 5 mg of melatonin increased total sleep time compared to a placebo.
Researchers conducted the study in 24 healthy, older adults to evaluate whether a high-doseor a low-dose melatonin supplement could improve sleep. The team found that the higher dose had a significant impact, increasing total sleep time compared to placebo by more than 15 minutes for nighttime sleep and by half an hour for daytime sleep. Results are published in the Journal of Pineal Research.
The body naturally produces the hormone melatonin, which helps regulate a person’s sleep-wake cycle with night and day. Melatonin levels peak at night. But among older people, levels of the hormone are often lower.
The team found that the low dose of melatonin did not lead to a statistically significant change in overall sleep time and that the changes that were seen were when sleep was scheduled during the biological day. Participants taking the 5 mg dose had a significant increase in total sleep time and sleep efficiency regardless of whether sleep was scheduled during the day or night.