How long does melatonin take to become fully effective?

Question

I've been taking it for two nights, and I'm getting sleep, but I'm really tired the next day. Will this tiredness continue?

Answer 1

sounds like it already is effective if you are getting some sleep.  its effects are not cumulative, but will make getting up the in the morning a little more difficult.  try setting your alarm 30 minutes earlier...

Answer 2

You may be so sleep deprived that it can take a week of good night's sleep before you feel rested again. So, the tiredness should decrease.