Hi . Melatonin does not produce any withdrawal symptoms, so there should be no concerns with stopping it cold-turkey. Melatonin can cause daytime sleepiness in some people, so coming off it is a wise move. If your daytime drowsiness doesn't improve within a day or so, your fatigue might be caused by something else. Have you talked with your doctor about it? Deficiencies in Vitamin D, B vitamins, folic acid or iron can cause significant daytime sleepness as can thyroid disorders. Your doctor can run quick bood tests to check your levels and rule those causes out. Everyone should have those tests once a year or so anyway. I hope this helps and that you are feeling more energetic during the day soon. Best wishes. - Lori (Team Member)