I want to know the effects of melatonin on test levels based on proper research(anecdotal experiences are also welcomed).I use melatonin and feel groggy next day even less than 1mg dose.
May I suggest that you also look at the research on sleep cycles as well. When I take melatonin, each cycle appears to be longer and deeper (I have an app that gives a rough estimate) and if I wake up in the middle of a deep cycle, I'm groggy much of the day. This happens without melatonin as well of course, but not as much.
Getting up when the body wakes to go to the bathroom (assuming it's just a little before the alarm goes off) or sleeping just a little longer does wonders. There are a few of apps that will help find the right cycle length for you. Good luck!
I am not a medical Dr, please keep in mind that this answer is for information purposes only, and is not intended to diagnose, treat or replace sound medical advice from your physician or health care provider.