Written by the ClariDay clinical team. Medically reviewed by Ali Salih, GPhC-registered Pharmacist Independent Prescriber. Reviewed 9 July 2026. Next review 9 January 2027. Yes. Mounjaro can make you feel tired, particularly during the first few weeks or after a dose increase. In most people it’s mild and temporary. The most common reason is eating much less than before, although dehydration and in some people, low blood sugar can also contribute [1]. Mounjaro (tirzepatide) i