Melatonin is an over-the-counter supplement used as a sleep aid. There is a recent trend of pediatric melatonin overdoses, which has been observed by doctors around the country. Over the past 10 years, the number of annual calls to poison control for pediatric melatonin overdoses has risen by 530 percent, and by 2020, poison control was receiving more calls about pediatric overdoses on melatonin than on any other substance. In addition, a broader study based on emergency-room data over a similar period reported a 420 percent increase in visits for pediatric melatonin ingestions. The ill effects of melatonin overdose seem mild at worst, including drowsiness, nausea, and vomiting. However, the number of kids who were affected was going up, up, up.

For adults, using melatonin for sleep is on the rise, and some may be using it at dangerously high levels. The overall use among the US adult population is still "relatively low," but the study does "document a significant many-fold increase in melatonin use in the past few years". Melatonin has been linked to headaches, dizziness, nausea, stomach cramps, drowsiness, confusion or disorientation, irritability, mild anxiety, depression, tremors, and abnormally low blood pressure. While short-term use for people with jet lag, shift workers, and those who have trouble falling asleep appears to be safe, long-term safety is unknown.

Melatonin supplements are widely available and commonly used as a sleep aid. Melatonin side effects are typically rare and mild but can include daytime sleepiness, headache, nausea, and dizziness. More research is needed to understand the effects of long-term melatonin use. It is important to talk to a doctor before taking melatonin during pregnancy or while breastfeeding, and people with medical conditions like those on dialysis or experiencing depression should also consult their doctor about melatonin safety.