Melatonin overdoses leading to severe toxicity and life-threatening symptoms are rare at any dose, says Glenna S. Brewster Glasgow, PhD, RN, assistant professor at Emory University’s Nell Hodgson Woodruff School of Nursing in Atlanta.
“Taking high doses can still cause unwanted side effects and disrupt natural sleep patterns,” Dr. Brewster Glasgow says.
“In children, melatonin overdose tends to present with milder symptoms compared with adults,” she says, “though the effects can last longer due to their smaller body size and slower metabolism.”
Brewster Glasgow says that signs of a melatonin overdose may include:
- Severe drowsiness or prolonged sedation
- Confusion, disorientation, and cognitive impairment
- Vertigo or loss of coordination
- Agitation or irritability
- Slurred speech and tremors
- Psychotic effects such as hallucinations and nightmares, which are rare
- Headache
- Dizziness
- Nausea
- Drowsiness
- Short-term depression
- Low-level anxiety
- Stomach cramps
- Low blood pressure
- Lower levels of alertness
- Seizures, in children
“These mild symptoms usually subside after adjusting the dosage,” Brewster Glasgow says. “If you experience more severe symptoms, it is advisable to contact your healthcare provider.”