Objective To evaluate the efficacy and safety of a gastric bypass stent system for weight loss and obesity‑associated metabolic parameters. Methods A sub‑analysis of a multicenter randomized control trial was conducted on data of 14 obese patients who were implanted the gastric bypass stent system under endoscopy in Beijing Friendship Hospital, Capital Medical University from March 2021 to October 2022. The device was removed after 12 weeks and the patients were followed up for 36 weeks. Outcomes included changes in excess weight loss (EWL), total weight loss (TWL), insulin resistance, liver enzymes, lipids and uric acid at 12, 24 and 36 weeks, and the safety of the device. Results Among the 14 patients, there were 9 males and 5 females, aged 34.3±7.4 years, with an initial body weight of 104.8±13.9 kg. Stents were removed in advance in 2 patients because of intolerable adverse reactions of the digestive tract. The remaining 12 patients completed follow‑up, and their EWL was 34.4%±25.5% at 12 weeks, 39.1%±37.5% at 24 weeks, and 27.3%±40.8% at 36 weeks. TWL was 8.7%±6.2%, 10.1%±10.2% and 8.3%±13.8%, respectively. The levels of homeostasis model assessment of insulin resistance (HOMA‑IR) at 12 weeks (4.81±3.71, P=0.022), 24 weeks (4.17±2.77, P=0.002) and 36 weeks (4.66±3.58, P=0.016) were statistically significant compared with baseline (7.03±3.59). The levels of alanine aminotransferase (ALT) were 48 (21‑124) U/L, 39 (14‑96) U/L, 27 (10‑86) U/L and 32 (16‑113) U/L at baseline, 12 weeks, 24 weeks and 36 weeks, respectively, and the changes of ALT were statistically significant at 24 weeks and 36 weeks (P=0.009, P=0.026 compared with baseline). The levels of aspartate aminotransferase (AST) were 30 (20‑62) U/L, 24 (15‑72) U/L, 22 (11‑56) U/L and 26 (13‑74) U/L at baseline, 12 weeks, 24 weeks and 36 weeks, respectively, and the change of AST was significant at 24 weeks (P=0.018 compared with baseline). However, the changes of uric acid and serum lipid were not statistically significant (P>0.05). The only severe adverse event was esophageal mucosal laceration during the process of explantation, which was successfully treated with endoscopic clips. There was no device migration, acute pancreatitis or hepatic abscess. Conclusion The gastric bypass stent system, relatively safe, has a good short‑term weight loss effect and improves insulin resistance and liver enzymes.