Weight loss injections are prescription medications that you administer yourself under the skin, typically in the abdomen, thigh, or upper arm. They contain active ingredients that mimic natural hormones in your body, primarily GLP-1 (glucagon-like peptide-1). These hormones target areas in the brain that control appetite and food intake, making you feel less hungry and more satisfied after eating smaller portions. Some advanced injections, like those containing tirzepatide, also mimic a second hormone called GIP to further enhance these effects. When combined with a healthy diet and regular exercise, weight loss injections help you consume fewer calories, leading to significant weight loss over time.