The popular over-the-counter sleep aid melatonin might have an even better use. A new study in the journal PLOS Biology suggests melatonin might be a treatment option to prevent COVID-19. Analysis of data from the Cleveland Clinic’s COVID-19 registry found that melatonin usage was associated with a nearly 30 percent reduction in the likelihood of testing positive. Now, this doesn’t mean everyone should start taking melatonin. We need randomized controlled trials to see if there really is a benefit of melatonin for people at risk for COVID-19.