Raptin is a recently discovered human hormone produced by the hypothalamus during sleep. It is cleaved from reticulocalbin-2 (RCN2).1 Raptin binds to glutamate metabotropic receptor 3 (GRM3) in hypothalamus and stomach neurons that inhibit appetite and gastric emptying, respectively.2 A 2024 study reported that it signals satiety to the gut, curbing appetite. Poor/inadequate sleep reduces raptin levels, increasing appetite. Raptin levels measured lower in people with obesity.3
Raptin levels peak during nighttime sleeping and decline during the day.3
A 2022 study reported that a lack of sleep increased ghrelin production, increasing appetite, and limits leptin, which disrupts satiety signals.3
A genetic study of 2,000 obese individuals led to the discovery of an RCN2 variant, which was present in a group of family members who suffered from Night Eating Syndrome (NES). The variant blocked raptin production, and all individuals with the variant were obese.3
References
References
- Cabot, Leonie; Fenselau, Henning (17 February 2025). "Raptin, a novel brain hormone links sleep health to body weight gain". Cell Research. doi:10.1038/s41422-025-01083-x.
- Xie, Ling-Qi; Hu, Biao; Lu, Ren-Bin; Cheng, Ya-Lun; Chen, Xin; Wen, Jie; Xiao, Yao; An, Yu-Ze; Peng, Ning; Dai, Yu; Xie, Genqing; Guo, Qi; Peng, Hui; Luo, Xiang-Hang (2025-01-29). "Raptin, a sleep-induced hypothalamic hormone, suppresses appetite and obesity". Cell Research: 1–21. doi:10.1038/s41422-025-01078-8. ISSN 1748-7838. PMC 11909135.
- Thompson, Bronwyn (2025-01-30). "Weight-loss breakthrough as new appetite-curbing hormone is found". New Atlas. Retrieved 2025-02-04.