>>120209000.3 to 1mg should do the trick. Anything else is less effective. Keep in mind that some of the melatonin probably broke down in the last decade, and that most dietary supplements contain a much higher concentration of melatonin than specified on the bottle (up to 450% more in some cases).
Also, practicing sleep hygiene by reducing blue-light exposure after dark is a much more efficient way to get melatonin into your brain.
