Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have recently emerged as a promising therapeutic option for patients to aid in weight loss; however, little is known about the potential psychiatric side effects of these medications. In this report, we present the case of a 64-year-old man who was started on the GLP-1 RA tirzepatide (Zepbound) and subsequently developed increased impulsivity, dysphoria, and aggression, which resolved with medication cessation. We suggest a potential relationship between GLP-1 RAs and mood, and we caution physicians to weigh the potential risks of the medications against the known benefits.