Over the prior 10 years, the number of annual calls to poison control for pediatric melatonin overdoses had risen by 530 percent. By 2020, poison control was receiving more calls about pediatric overdoses on melatonin than on any other substance. The year before melatonin usage began to rise, the CDC launched an initiative to reduce pediatric overdoses as a whole. A Canadian study from 2017 that looked at melatonin supplements more generally, not just at gummies, reached a similar conclusion. But the recent spate of pediatric melatonin overdoses represents another big one: the products’ maddening irregularity.