This study aims to elucidate the mechanism behind the potent weight loss induced by dual amylin and calcitonin receptor agonists (DACRA) through comparison of the novel DACRA KBP-088 with the amylinomimetic davalintide with regard to in vitro receptor pharmacology and in vivo efficacy on food intake and body weight. KBP-088 and davalintide were tested for their ability to activate the amylin and calcitonin receptors as function of dose and time. Two doses of KBP-088 (1.67 and 5.0 μg/kg) were compared with similar davalintide doses in high-fat diet (HFD)-fed rats receiving subcutaneous dosing once daily for 62 days. Glucose tolerance was assessed after 3 and 7 wk of treatment. KBP-088 demonstrated activation of amylin and calcitonin receptors and prolonged receptor activation compared with davalintide as well as a potent reduction of acute food intake. KBP-088 transiently reduced food intake and induced and notably sustained a significant ∼16% vehicle-corrected weight loss without significant weight loss in the calorie-restricted control groups. Additionally, KBP-088 reduced white adipose tissues and adipocyte hypertrophy. Finally, KBP-088 alleviated hyperinsulinemia and improved oral glucose tolerance even with significantly lower insulin levels after 3 and 7 wk of treatment. KBP-088 is a potent amylin and calcitonin receptor agonist with prolonged receptor activation compared with davalintide. Moreover, KBP-088 induced and sustained significant weight loss and reduced overall adiposity and adipocyte hypertrophy in HFD rats. Finally, KBP-088 improved oral glucose tolerance and alleviated hyperinsulinemia, underscoring the potential of KBP-088 as an antiobesity agent with benefits on glucose control.