Tirzepatide begins to exert its effects on the body immediately after administration, but visible results in terms of weight loss emerge over time. Many patients start to notice initial weight loss within the first 4 weeks of treatment. Significant weight reduction is usually more apparent around the 20-week mark. It's important to understand that the medication's full impact on appetite and metabolism develops gradually as the dose is increased over time, following a carefully structured titration schedule designed to minimize side effects while maximizing efficacy.