Melatonin may stave off age-related vision loss, study hints

Melatonin supplements may reduce the risk of developing age-related macular degeneration (AMD), the most common cause of severe vision loss in people over age 50. 

Researchers uncovered this link after analyzing electronic medical records gathered between 2008 and 2023 from patients in the U.S. 

The scientists examined records from more than 238,000 people over age 50 who had no History of AMD, about 121,000 of whom reported taking melatonin. From this data, the scientists estimated that the individuals taking melatonin were 58% less likely to go on to be diagnosed with AMD within the 15-year study period than those who were not. 

The former group had to have reported to their doctor that they were taking melatonin at least four times within the 15-year window, with a minimum three-month gap between these reports. In the U.S., melatonin is considered to be a dietary supplement, so it can be purchased without a prescription. 

Related: Kids' use of melatonin 'exceedingly common,' Colorado study finds

Although it revealed an interesting link, the study has some major caveats. 

Notably, over-the-counter melatonin supplements can vary considerably in terms of their purity and the concentration of ingredients included. Studies have suggested that melatonin gummies sold in the U.S. often contain much higher doses than listed — or more rarely, they contain no melatonin at all. This means that the actual dose of melatonin that people were taking in this study is unknown.