How long does it take for Zepbound to work?
In clinical studies submitted to the FDA for approval, patients lost weight during the first 4 weeks of taking Zepbound (tirzepatide). How quickly you lose weight on Zepbound depends on various factors, including your starting weight, the dose you are taking, diet, and physical activity level.
What is Zepbound used for?
Zepbound is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist. It’s injected under the skin once a week in addition to diet and exercise for long-term weight management in adults with a body mass index (BMI) of:
- 30 kg/m2 or more, or
- 27 kg/m2 or more and at least one weight-related health condition (e.g., high blood pressure, type 2 diabetes, obstructive sleep apnea)
Zepbound is also used to treat moderate-to-severe obstructive sleep apnea in adults with obesity.
Does Zepbound work immediately?
You won’t notice weight-loss effects from Zepbound right away. After injecting a dose of Zepbound, it reaches maximum levels in your body between 8 and 72 hours. This suggests that the medication can start to work the same day after taking a dose to suppress your appetite. However, your healthcare provider will need to slowly titrate your dose up to the most effective dose of Zepbound. They will start you on a low dose (2.5 mg) for the first 4 weeks of treatment. This dose is meant to get your body used to the medication. After 4 weeks, your dose will be raised to 5 mg once weekly. The recommended maintenance doses of Zepbound are 5 mg, 10 mg, or 15 mg.
Zepbound works by affecting your appetite, which helps you eat less calories. Therefore, it will take some time to lose weight. The amount of time it takes to lose weight while taking Zepbound will be different for each individual person. This is because how quickly you lose weight from Zepbound depends on factors like eating habits and how much physical activity you are getting.
Related questions
- Zepbound vs. Mounjaro: Comparison Guide for Weight Loss and Diabetes Treatment
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When is the best time to take the Zepbound shot?
According to the manufacturer, Zepbound can be injected at any time of the day. The time of day shouldn’t affect how well the medication works for you because it has a long half-life, which means it stays in your body for a long time. Make sure to inject it once a week on the same day every week. You can inject Zepbound with or without food.
This is not all the information you need to know about Zepbound for safe and effective use and does not take the place of your doctor’s directions. Review the full patient medication guide and discuss this information and any questions you have with your doctor or other health care provider.
References
- Jastreboff, A. M., et. al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. In: The New England Journal of Medicine. DOI: https://doi.org/10.1056/nejmoa2206038
- Jensen, T. L. ,et. Al. (2024). The Body weight Reducing Effects of Tirzepatide in People with and without Type 2 Diabetes: A Review on Efficacy and Adverse Effects. In: Patient Preference and Adherence. DOI: https://doi.org/10.2147%2FPPA.S419304
- Zepbound [package insert]. (Updated July 2025). Eli Lilly and Company. Accessed on August 13, 2025 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b
Read next
How much is Zepbound with or without insurance?
Zepbound may cost $25 if you have insurance, or without insurance, Zepbound can cost $349 for a 2.5mg vial and $499 for a 5mg vial
Continue reading
Can you get tirzepatide from a compounding pharmacy?
Some pharmacies or clinics may supply compounded versions of medicines like tirzepatide (Mounjaro, Zepbound) and semaglutide (Ozempic, Wegovy) to patients, but the FDA has issued safety warnings about this practice. Concerns have risen over active ingredients, side effects and labeling of these compounded products. Continue reading
How do Zepbound and Wegovy compare?
Zepbound and Wegovy are two FDA-approved weight loss medications with similar side effects. Research is ongoing to determine whether patients lose more weight with Zepbound or Wegovy. In clinical trials, adults taking Zepbound lost more weight compared to adults who took Wegovy.
Continue readingSee also:
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Drug information
- Zepbound Information for Consumers
- Zepbound prescribing info & package insert (for Health Professionals)
- Side Effects of Zepbound (detailed)
- Zepbound user reviews (426)
Related support groups
- Zepbound (22 questions, 30 members)
- Weight Loss (Obesity/Overweight) (872 questions, 1,513 members)