Search for articles or Rx savings
Key takeaways
You’ll start noticing weight loss after about four weeks of taking Zepbound, once it reaches a steady level in your body.
Zepbound has a long half-life of about 5 days, so if you experience side effects and discontinue the medicine, it will take several weeks to completely clear from your system.
Zepbound (tirzepatide) is a brand-name medication that is FDA approved for weight loss, weight management, and obstructive sleep apnea. It contains the same active ingredient as the Type 2 diabetes medication Mounjaro. Because Zepbound targets both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, it’s known as a dual GIP/GLP-1 receptor agonist. In this way, Zepbound is similar but slightly different from GLP-1 prescription medications, such as Ozempic (semaglutide) and Wegovy (semaglutide), which only target GLP-1 receptors.
Clinical studies show that Zepbound starts working for weight loss after about four weeks, as the medication reaches a steady level in your body. Though tolerability can vary from person to person, Zepbound is associated with some common side effects, drug interactions, and other risks that may cause some people to discontinue the medication. Even after stopping Zepbound, it can stay in your system for several weeks, though side effects should taper off as more time passes from your last dose.
Save up to 80% on Zepbound with SingleCare
Different pharmacies offer different prices for the same medication. SingleCare helps find the best price for you.
How long does Zepbound stay in your system?
Many prescription drugs, including Zepbound, have what’s called an elimination half-life. This refers to the amount of time it takes for the body to clear half a dose of a drug, so only half the dose remains in your system. It’s important to know the half-life of a drug because this helps determine how often it’s taken.
The half-life of Zepbound is about five days, says Richele Corrado, DO, a double board-certified internist and obesity medicine provider in Washington, DC. This means that 50% of the medication remains in the body after five days, 25% after 10 days, 12.5% after 15 days, and so on. How long is Zepbound ultimately in your system? “Given the long half-life of the medication, it is expected that Zepbound can still be in your system at low doses for up to 30 days,” Dr. Corrado says.
While Zepbound has a rather long half-life, meaning a portion of it stays in your system for several weeks, it peaks rather early on. “Peak effect of the medication is typically 8 hours after an injection,” Dr. Corrado says. However, this can vary on an individual basis. “In some individuals, peak effect may be up to 72 hours post-injection,” she says.
Since Zepbound is injected on a weekly basis, each dose isn’t fully eliminated from the body before the next dose is administered. This means that the body will reach a steady-state concentration of the medication after a certain number of doses. People taking Zepbound typically achieve a steady-state concentration of the medication after four injections, Dr. Corrado says. If you stop taking the medication, it can take about a month for the medication to fully clear from your system.
Factors that influence how long Zepbound stays in your system
The half-life of Zepbound is about five days, with peak effects around eight to 72 hours after each weekly injection. However, these are estimates, and there may be slight variations from person to person. “Everyone’s body is different,” Dr. Corrado says. While there may be more yet to be discovered about Zepbound’s duration in the body, here’s what may influence how long it stays in your system.
1. Metabolism
Metabolism refers to chemical reactions in the body that turn food into energy, but it can also refer to how the body processes medications. “Metabolism can affect how long Zepbound stays in your system, but not dramatically,” says Supriya Rao, MD, an obesity medicine provider based in the Greater Boston area.
However, this isn’t fully understood. “Some people appear to absorb and metabolize the medication differently, but it’s not clear what characteristics drive better absorption of the drug,” Dr. Corrado says.
2. Dosage
Zepbound comes in pre-filled, single-dose pens that are administered via subcutaneous injection once per week. The pens come in six doses: 2.5 milligrams (mg), 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Eli Lilly, the manufacturer, also offers Zepbound in vial form, which requires you to draw up your weekly dose with a syringe and can be ordered directly from the company. These vials come in the four lower doses and will soon be available in all six dosage strengths. All doses of Zepbound have the same 5-day half-life, Dr. Corrado says. So, regardless of dose, Zepbound will clear from your system at the same rate.
“Higher doses result in higher plasma concentrations,” Dr. Corrado says. They’re also associated with greater outcomes for weight loss. Research demonstrates that higher doses (10 mg and 15 mg) of tirzepatide are more effective at improving body mass index (BMI) and resulting in greater weight loss in adults with overweight or obesity.
However, this doesn’t necessarily mean that higher doses of Zepbound stay in your system for significantly longer. “Higher doses can stay in your system a little longer simply because there’s more medication present for your body to process, but the difference isn’t significant,” Dr. Rao says.
Side effects and risks of Zepbound
When taking prescription drugs, it’s important to be aware of the possible side effects and risks. Zepbound is no exception. The most common side effects of Zepbound are gastrointestinal, Dr. Corrado says. This can include symptoms like:
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Abdominal pain
- Belching
- Heartburn
- Indigestion
Though gastrointestinal side effects are common, Zepbound is generally safe and well tolerated, as shown in a meta-analysis. Other common side effects of Zepbound can include allergic reactions, reactions at the injection site, tiredness, and hair loss.
There are more serious side effects of Zepbound, but they’re less common. For example, Zepbound may cause severe problems that affect the stomach, gallbladder, or pancreas. It could also cause severe allergic reactions and low blood sugar. In animal studies, Zepbound has been linked to thyroid cancer, but it’s not known if this risk applies to humans. You should not use Zepbound if you have a personal or family history of medullary thyroid carcinoma (MTC), or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Not everyone who takes Zepbound will experience side effects. For some people, the side effects are mild and improve over time as your body adjusts to the medication. For others, they can be severe. If you’re taking Zepbound and experiencing side effects that aren’t going away or getting better, inform your prescribing healthcare provider.
If you take any medications for other health conditions, it’s also important to be aware of possible drug interactions. For example, Zepbound may interact with oral contraceptives or diabetic drugs. You may also need to adjust the timing of certain medicines that you take around the same time as Zepbound—check with your healthcare provider.
How long does it take for side effects to go away after stopping Zepbound?
Though some side effects are mild, they can negatively affect the drug’s efficacy and patient tolerance, research has found. Unpleasant side effects can cause some people to discontinue the medication, leaving them wondering: When will the side effects of Zepbound go away after stopping it altogether?
Fortunately, the side effects should dissipate shortly after your last dose. “Most side effects of Zepbound tend to improve within a few days to a week after stopping, though some may linger a little longer since the medicine will stay in your system for several weeks,” Dr. Rao says. This medication isn’t associated with classic withdrawal symptoms, Dr. Rao adds.
However, this doesn’t mean you should stop taking the medication abruptly or without the supervision of a healthcare provider. When you stop taking Zepbound, which works for weight loss by reducing your appetite, your appetite and food cravings may return to normal. “Some folks may notice a return of appetite or weight regain if lifestyle habits aren’t in place,” Dr. Rao says.
Zepbound works by mimicking the actions of two hormones, GIP and GLP-1, to suppress appetite and slow digestion. This explains why it’s effective as a chronic weight management treatment. However, Zepbound isn’t a quick fix, Dr. Rao says. It’s intended to be combined with lifestyle changes, such as a reduced-calorie diet and increased physical activity, for weight loss that’s sustainable. Researchers recommend lifestyle modifications, such as diet and exercise, as an adjunct to anti-obesity medications but say more studies are needed on their role.
Zepbound accumulation and longevity
Zepbound isn’t habit-forming, and stopping it doesn’t cause withdrawal symptoms. But Zepbound’s long half-life means that it stays in your system for several weeks. That doesn’t necessarily mean it accumulates to alarming levels, however. Here’s how Zepbound leaves the body after taking it consistently.
“It doesn’t build up in a toxic way, but because Zepbound is taken weekly and has a long half-life, levels become more consistent in your system over time,” Dr. Rao says. Taking the medication consistently is how you reach steady-state concentrations, but those concentrations dip when you stop taking the medication. So, where does the medication go if it doesn’t accumulate? “The body eliminates broken-down metabolites of Zepbound via urine and feces,” Dr. Corrado says.
Elimination aside, Zepbound isn’t designed for short-term use, Dr. Rao says. Many of the clinical studies looked at Zepbound’s effects when used for more than a year, suggesting that it’s most effective when used long-term. What’s more, stopping the medication is associated with regaining weight.
In one clinical trial published in The New England Journal of Medicine, adults with obesity had significant reductions in body weight after 72 weeks of taking tirzepatide. Those taking the highest dose, 15 mg, experienced the largest weight reductions—an average of 20.9%. In another clinical trial, adults with obesity or overweight lost an average of 25.3% of body weight while taking tirzepatide for 88 weeks. Interestingly, researchers found that participants who were switched to a placebo (inactive treatment) nearly halfway through regained an average of 14% of their body weight.
Zepbound alternatives
Zepbound is used for weight loss, weight management, and obstructive sleep apnea. However, if the side effects are too much for you, it’s not your only option. Talk to your healthcare provider about any side effects you may be experiencing. He or she may recommend lowering your dose, giving your body more time to adjust to the medication, or switching to a different medication.
Some alternatives to Zepbound for weight loss include:
| Zepbound alternatives | |
|---|---|
| Drug name | Coupons |
| Wegovy (semaglutide) | Coupons |
| Saxenda (liraglutide) | Coupons |
| Qsymia (phentermine/topiramate) | Coupons |
| Contrave (naltrexone/bupropion) | Coupons |
| Xenical, Alli (orlistat) | Coupons |
There are many factors that go into determining the right treatment plan for you, and everyone’s journey may look different. There are pros and cons of taking Zepbound, which you should discuss with a healthcare professional before stopping the drug. Your healthcare team can advise you on the right treatment plan for you.
- Zepbound, DailyMed (2025)
- Analysis of tirzepatide acquisition costs and weight reduction outcomes in the United Kingdom: Insights from the SURMOUNT-1 study, Advances in Therapy (2025)
- The role of lifestyle modification with second-generation anti-obesity medications: Comparisons, questions, and clinical opportunities, Current Obesity Reports (2023)
- Efficacy and safety of once-weekly tirzepatide for weight management compared to placebo: An updated systematic review and meta-analysis including the latest SURMOUNT-2 trial, Endocrine (2024)
- Tirzepatide-induced gastrointestinal manifestations: A systematic review and meta-analysis, Cureus (2023)
- Tirzepatide once weekly for the treatment of obesity, The New England Journal of Medicine (2022)
- Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity: The SURMOUNT-4 randomized clinical trial, Journal of the American Medical Association (2024)