Glucagon-like peptide-1 (GLP-1) receptor agonists became the most prescribed drugs for weight loss. This study aimed to investigate adverse events of GLP-1 receptor agonists using Twitter and KIDS-KAERS database (KIDS-KD). 116 Korean tweets on Twitter and 1,701 liraglutide-adverse event combinations from KIDS-KD were used for analysis. The most common adverse events were nausea (37.76%), vomiting (12.59%), dyspepsia (9.79%), dizziness (4.90%), and somnolence (4.90%) on Twitter. Adverse events observed in the post-marketing surveillance such as somnolence, myalgia, chest pain/ discomfort, and parosmia were found on Twitter. In KIDS-KD, injection site rash (13.46%), injection site pruritus (10.76%), nausea (10.64%), vomiting (6.41%), and injection site reaction (5.29%) were commonly reported. Signals were injection site rash (reporting odds ratio [ROR] = 616.1), injection site pruritus (ROR = 477.7), vomiting (ROR = 2.4), injection site reaction (ROR = 222.0), pruritus (ROR = 2.5), injection site bruising (ROR = 45.8), injection site pain (ROR = 36.3). Subgroup analysis revealed that injection site rash (n = 16, ROR = 46.6) and acne (n = 3, ROR = 39.2) met signal criteria in men and women, respectively. Twitter analysis identified adverse events that were not found in clinical trials, and KIDS-KD subgroup analysis suggested the possibility of acne being a safety signal. Social media and KIDS-KD were useful for pharmacovigilance.