What is the overdosage amount for melatonin?

>10 mg. Recommended dose is up to 10 mg per night. Larger doses may produce excessive drowsiness. Other central nervous system depressants may enhance the effects of melatonin.
Melatonin Overdose. Above 10mg is above recommended doseage. A serious melatonin overdose in an adult is usually between 20-50mg. A melatonin overdose could lead to symptoms like marked sedation, headache, nausea, vomiting, upset stomach, low blood pressure, dizziness, confusion, disorientation, tremor, liver problems, weakness & seizures.