By Victoria Bouhairie, MD, as told to Michele Jordan
Victoria Bouhairie, MD, is endocrinologist with board certifications in endocrinology, obesity medicine, and lifestyle medicine. She is senior vice president of obesity care and prevention at the American Diabetes Association. The information here represents her knowledge and experience as a medical professional.
Tirzepatide was approved by the FDA for weight loss under the brand name Zepbound in 2023. Before that, it was used to help with type 2 diabetes to control blood sugar. Here's what to keep in mind if you're trying it for weight loss.
Who typically benefits from this treatment?
Tirzepatide has several FDA-approved uses.
As Mounjaro, it helps improve blood sugar in adults and children ages 10 years and older with type 2 diabetes. It can reduce the risk of major cardiovascular events in adults with type 2 diabetes.
As Zepbound, it's approved for chronic weight management in adults with obesity, or in overweight adults who have at least one weight-related health condition. It's also approved to treat moderate to severe obstructive sleep apnea in adults with obesity.
Research also suggests tirzepatide may help with some obesity-related conditions, including high blood pressure, certain types of heart failure, and MASH (metabolic dysfunction-associated steatohepatitis) with liver fibrosis.
What sets this treatment apart from others?
Tirzepatide is different because rather than activating one hormone (GLP-1), it activates two hormone receptors, GIP and GLP-1. These receptors are found in the brain, pancreas, and digestive system. They help regulate your body's response to food by regulating blood sugar and appetite.
They send signals to your brain that control appetite, slowing how quickly food leaves your stomach and making you feel fuller.
Together, these effects can reduce appetite and food intake, improve blood sugar control, and support weight reduction.
Can you tell me about how well this treatment works and how quickly people might see results?
Tirzepatide can work very well for both blood sugar control and weight loss. In people with type 2 diabetes, studies have shown drops in A1c of about 2 percentage points, and many people reach their recommended blood sugar goals. In people with overweight or obesity without diabetes, studies found average weight loss of about 15% to 21% over 72 weeks, depending on the dose.
Some people may notice changes in appetite, fullness, or blood sugar within the first few weeks, but the biggest benefits usually happen gradually. The medication starts at a low dose and is typically increased every four weeks, so weight loss and improvements in related health conditions can continue for many months.
It's also important to remember that success isn't just about the number on the scale. We're also looking for improvements in blood sugar, other health conditions, physical function, and overall well-being.
What kinds of things affect how well the drug works?
People can respond differently to tirzepatide. Your individual biology, the condition being treated, other health conditions and medications, nutrition, physical activity, sleep, how consistently the medication is taken, side effects, and whether you're able to stay on treatment can all affect the response. People with type 2 diabetes, for example, may have different weight responses than people without diabetes, and treatment goals may also differ depending on whether the focus is blood sugar, weight, or an obesity-related disease or complication.
Your goals are important, too. Someone taking tirzepatide to manage type 2 diabetes may have different goals from someone using it for weight loss alone.
The dosage also matters. Tirzepatide is often started at a low dose and increased gradually. The goal isn't to get everyone to the highest dose. The right dose for you (maintenance dose) is the one that gives you the best results while keeping side effects manageable. For the best weight loss results, experts suggest combining the medication with a healthy diet, physical activity, and behavioral approaches that support long-term health.
Is this treatment generally considered safe?
Tirzepatide has been studied in large clinical trials and is generally considered safe. Being a good fit for the medication and close monitoring by your doctor are key. But like all medications, it has potential risks and is not right for everyone.
The FDA prescribing information includes a boxed warning about thyroid C-cell tumors based on animal studies. We don't know whether tirzepatide causes these tumors in humans. It should not be used in people with a personal or family history of medullary thyroid carcinoma, a rare type of thyroid cancer, or in people with multiple endocrine neoplasia syndrome type 2 (MEN2).
Other important risks include severe gastrointestinal problems, pancreatitis, gallbladder disease, serious allergic reactions, and kidney injury that can happen with dehydration from nausea, vomiting, or diarrhea. Tirzepatide can also increase the risk of low blood sugar when you use it with insulin or certain other diabetes medications. It's important to review your medical history and all medications with your doctor before starting treatment.
What sort of side effects can people expect, and are there ways to handle them?
The most common side effects of tirzepatide are gastrointestinal. They include nausea, diarrhea, vomiting, constipation, stomach pain or discomfort, and indigestion. Some people may also have decreased appetite, burping, or reflux. These side effects are often more noticeable when you start treatment or increase the dose. And for many people, they improve over time.
Eating smaller meals, eating slowly, stopping when you feel full, avoiding foods that worsen symptoms, and drinking plenty of fluids can help. Staying hydrated is especially important if you have vomiting or diarrhea.
Doctors also usually increase the dose gradually. If side effects are bothersome, your doctor may keep you at the same dose longer before increasing it.
How do you take this treatment? Will people need any regular tests or checkups?
Tirzepatide is an injection you give yourself once a week, on the same day each week. Your doctor will likely start with 2.5 mg once weekly for four weeks and then increase gradually, usually in 2.5-mg steps up to every four weeks based on how you're tolerating it.
The follow-up and testing you need will depend on your health. If you have type 2 diabetes, your doctor may monitor your A1c and blood sugar. Or you may need tests of your blood pressure, kidney function, or other obesity-related conditions.
Experts recommend follow-up at least monthly during the first three months, and during any dosage changes. Your doctor may suggest follow-ups every three months for the first year and then every six months after that. These visits are important to see if the medication is working, your side effects are manageable, and if you're making progress toward your health goals.
Are there any types of people who shouldn't take this treatment, like those with certain health conditions or who are taking other medications?
Tirzepatide is not right for everyone. You should not take it if you have a personal or family history of medullary thyroid carcinoma or MEN2, or if you've had a serious allergic reaction to tirzepatide or any of its ingredients.
Your doctor may take extra precautions if you have a history of pancreatitis, gastroparesis, gallbladder disease, kidney problems, dehydration risk, diabetes, or diabetic retinopathy. Talk to your doctor if you notice severe, persistent belly pain, especially if it radiates to the back and comes with or without vomiting.
Zepbound is also not safe for weight loss in pregnancy. It may affect how your body absorbs some oral medications and may increase the risk of low blood sugar when combined with insulin or sulfonylureas. It can also make oral hormonal birth control less effective. Your doctor may recommend a non-oral contraceptive or an added barrier method after starting treatment and after dose increases.
How much does this treatment cost? Will insurance cover it, or are there options for financial assistance?
Cost varies depending on which medication you're prescribed, why you're taking it, and your insurance plan. Coverage for Mounjaro for type 2 diabetes may be different from coverage for Zepbound for weight management or sleep apnea, and some plans require prior authorization.
If you have commercial insurance, drugmaker savings programs may lower your cost. Some eligible patients pay as little as $25, depending on coverage and program rules. These savings cards generally aren't available with Medicare, Medicaid, TRICARE, or VA coverage.
If you're paying out of pocket, Lilly offers self-pay options for Zepbound. A Medicare GLP-1 Bridge program may also allow some eligible Medicare Part D patients to pay a reduced cost.
Because prices and coverage can change, check with your insurer, health care team, and the drugmaker before starting treatment.
How can people find out more about whether this treatment would be a good fit for them?
Whether tirzepatide is a good fit depends on your age, medical history, current health conditions, medications, treatment goals, potential benefits and risks, side effects, cost, and personal preferences. The best place to start is with a talk with your doctor.
If you have type 2 diabetes, they may look at your blood sugar goals, cardiovascular risk, other diabetes medications, and your risk of low blood sugar. If you're trying it for weight loss, they may review more than body mass index (BMI) and look at your weight history, obesity-related diseases and complications, nutrition, physical activity, sleep, emotional health, and previous treatments. If you have obstructive sleep apnea or other related conditions, talk to your doctor about that also.
Ultimately, you and your doctor should work together to decide if tirzepatide, or another treatment, best fits your health goals.
Can you give me some insights into the research and studies behind this treatment?
Tirzepatide has been studied in a wide range of clinical research across several conditions.
Studies looked at people with type 2 diabetes, cardiovascular disease, prediabetes, obstructive sleep apnea, obesity-related heart failure, and MASH with liver fibrosis.
The research is positive so far — showing sustained weight loss and a significant reduction of prediabetes progressing to type 2 diabetes, compared with a placebo.
Researchers have also looked at obesity-related diseases and complications.
An important takeaway is that research is exploring weight loss and other improvement in overall health and conditions linked with obesity. The 2026 Standards of Care also emphasize that if a medication is working, continued treatment is often needed to help maintain the benefits over time.
What can you say about the sleep apnea benefits that are newly listed as an indication for this drug?
Zepbound is the first FDA-approved medication to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity. It is now included in treatment recommendations for people who are overweight or obese with moderate to severe OSA.
In a one-year study of 469 adults, researchers looked at people who were using PAP therapy for sleep apnea and those who were not. Zepbound significantly reduced the number of times that people in the study stopped breathing or had shallow breathing during sleep. Some people improved enough that they no longer met the criteria for obstructive sleep apnea.
The studies also showed weight loss and improvements in cardiovascular risk factors.
One important point: If you're using tirzepatide for sleep apnea, don't stop CPAP or other PAP therapy on your own. Even if your symptoms improve, talk with your doctor before making any changes to your current sleep apnea treatment.
