I want to take melatonin to help me sleep for an overseas flight. What dosage should I take?

Hello Anon

Thank you for writing!

Unfortunately we cannot answer this question, as we don't know how long that flight is (over night flights can be answer from 5-10+ hours) nor any other medications you are taking which could pose a risk.
Your best bet is to put call into your doctor's office where a nurse there could help you out over the phone. Also, be sure to read the recommendations on the bottle of melatonin and potential side effects.
Best,
Susan