A 23‑year‑old woman with slowly progressive type 1 diabetes (a form of LADA) struggled to control blood sugar and weight despite insulin, dapagliflozin, and metformin. When she started taking oral semaglutide, her blood sugar dropped, she lost weight, and she could stop insulin. She also reported healthier eating habits after starting the drug.

The role of glucagon-like peptide-1 receptor agonists (GLP-1RAs) as a standard treatment for slowly progressive type 1 diabetes mellitus (SPIDDM), a condition akin to latent autoimmune diabetes in adults (LADA) or latent autoimmune diabetes in the young (LADY), and a term primarily used in Japan, remains to be fully established. However, these agents show potential as a therapeutic option. We report a case of a 23-year-old Japanese woman who had SPIDDM (probable) since the age of 19 and had poor glycemic and weight control despite treatment with insulin, dapagliflozin, and metformin. Following the initiation of oral semaglutide (a GLP-1 RA), significant improvements in glycemic levels and weight were observed, enabling the discontinuation of insulin. Notably, beneficial changes in her eating behavior were also evident after oral semaglutide administration. This case suggests that GLP-1 RAs are a beneficial therapeutic option for glucose and weight management in patients with SPIDDM (probable), particularly when accompanied by favorable alterations in eating behavior, thus warranting further investigation.