Can I take more than 10 mg of melatonin a night?

The recommended dose of Melatonin for difficulty falling asleep is 5 mg 3 to 4 hours before bed, but if you have problems remaining asleep then a high dose (10mg) or controlled-release formulation is recommended.

The U.S. Food and Drug Administration does not strictly regulate supplements so research regarding toxicity dosing is limited. Research does suggest that Melatonin is likely safe when taken at recommended doses, typically 1-20mg, for up to three months.

For more information talk with your doctor.

https://www.drugs.com/melatonin.html