Tirzepatide vs. semaglutide for weight loss: which is better?

If you're on a weight loss journey, you’re probably familiar with GLP-1 medications like semaglutide and tirzepatide (or maybe you know them better by their respective brand names for weight loss, Wegovy and Zepbound). 

While they share some similarities, tirzepatide and semaglutide are different medications that work in slightly different ways. So, how do they compare, and is one more effective than the other? 

Clinical trial data suggests that tirzepatide may lead to more significant weight loss than semaglutide, but that may not be the only thing to consider when comparing these medications. Various factors—including potential side effects, costs, and other health benefits—can come into play when determining which medication best suits your unique needs and goals. 

“I have patients who have had excellent success with both medications,” says Marlena Klein, DO, a board-certified physician in Internal Medicine.

Keep reading to learn more about tirzepatide and semaglutide, with information on cost, side effects, and weight loss outcomes that can help you and your healthcare provider decide which weight loss injection is right for you. 

Semaglutide belongs to GLP-1 receptor agonists, while tirzepatide is a dual-agonist that acts on GLP-1 and GIP receptors.

Semaglutide and tirzepatide are the active ingredients in several popular medications:

• Ozempic (semaglutide) is approved by the US Food and Drug Administration (FDA)  to treat type 2 diabetes. It’s also approved to reduce the risk of chronic kidney disease, kidney failure, and major cardiovascular events in certain populations. 

• Wegovy (semaglutide) is approved by the FDA for weight loss in adults with obesity or overweight who also have a weight-related health condition, such as type 2 diabetes, high cholesterol, or heart disease. Wegovy is also approved to help reduce the risk of heart attack and stroke in people with obesity or overweight who have heart disease.

• Mounjaro (tirzepatide) is approved to help regulate blood sugar in adults with type 2 diabetes. 

• Zepbound (tirzepatide)is FDA-approved for weight loss in adults with obesity or overweight who have at least one weight-related health condition (such as type 2 diabetes or high blood pressure). It is also approved to treat obstructive sleep apnea in adults with obesity. 

For this article, we’ll focus on the branded versions of semaglutide and tirzepatide indicated for weight loss (Wegovy and Zepbound) and may use these names interchangeably where relevant.

While these medications are similar, semaglutide and tirzepatide are not the same. Let’s take a quick look at each medication to understand their key differences. 

What is semaglutide?

• Drug class: Semaglutide is a glucagon-like peptide-one receptor agonist, or GLP-1. 

• Brand name(s) for weight loss: Wegovy is currently the only brand name for semaglutide that is FDA-approved for weight management. 

• Mechanism of action: Semaglutide works by mimicking the hormone GLP-1, a type of hormone produced in the intestines that can help regulate blood sugar and appetite. 

• Form and frequency: Wegovy comes in a single-use pre-filled pen that you inject under the skin once per week on the same day each week. 

• Dose strengths: Wegovy comes in five dose strengths: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg. 

• Cost: Wegovy costs $1349.02 without insurance or other savings/discount programs.  

What is tirzepatide?

• Drug class: Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist.

• Brand name for weight loss: Tirzepatide is approved for weight loss under the brand name Zepbound.  

• Mechanism of action: Tirzepatide mimics both GLP-1 and GIP, another gut hormone that can impact blood sugar and appetite. 

• Form and frequency: Zepbound comes in either a single-dose pen or a single-use vial that you inject with a syringe. You inject Zepbound once weekly on the same day each week.  

• Dose strengths: Zepbound comes in six dose strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. 

• Cost: ​​Zepbound pens cost $1086.37 per month before insurance or other discounts and savings programs. You can also access Zepbound vials (2.5 mg and 5 mg) through Lilly Direct for $349 and $499, respectively.  

Tirzepatide and semaglutide work by mimicking a gut hormone called GLP-1, which is produced in the intestines when you eat. Both medications target and bind to GLP-1 receptors in the brain, pancreas, and stomach to help promote weight loss in several ways:

• Regulating blood glucose (sugar). Both medications can help stimulate the pancreas to release the hormone insulin, which can help your cells convert food into energy and lower blood sugar levels.  

• Reducing appetite. Tirzepatide and semaglutide both bind to receptors in the brain to dampen hunger cues, which can help reduce appetite and overall food intake. Some people also report less “food noise,” an unofficial term that describes intrusive thoughts about food. 

• Delaying gastric emptying. These medications also help slow down the rate at which food moves from your stomach to your lower intestine. This can increase satiety (how satisfied you feel after eating) and help you feel full longer. 

While semaglutide binds to GLP-1 receptors, tirzepatide binds to both GLP-1 and GIP receptors. Some research suggests that tirzepatide’s dual-action mechanism may make it more effective for weight loss and blood sugar control. 

The combined effect of these actions may lead to significant weight loss, though experts note that neither medication is meant to work in isolation. Both Zepbound and Wegovy are designed to be used in combination with a balanced diet and regular exercise.

“Healthy patterns for diet and exercise are important for good health for everyone—whether or not they are taking one of these medicines,” says registered pharmacist Ted Kyle, RPh, MBA.

In addition to aiding weight loss, tirzepatide and semaglutide may offer a range of health benefits, including:

• Insulin sensitivity. Tirzepatide’s dual-action mechanism may enhance insulin sensitivity, helping the body use insulin more effectively, which is crucial for managing blood sugar levels. Other research shows that semaglutide’s impact on body weight may also help combat insulin resistance. 

• Cardiovascular benefits. Both medications may offer cardiovascular benefits. Some research shows that tirzepatide may positively affect cholesterol levels and help lower blood pressure. Semaglutide may reduce cardiovascular risks, especially in individuals with type 2 diabetes. Research shows it may lower the chances of heart attacks, strokes, and other related cardiovascular events.

• Impact on metabolic syndrome. Tirzepatide may help address metabolic syndrome symptoms, including high cholesterol, elevated blood pressure, and insulin resistance, which can lower the risk of developing heart disease and other complications.

Both tirzepatide and semaglutide can aid in weight loss, with higher doses often leading to more significant results. However, research suggests that tirzepatide may be more effective.

A recent cohort study compared the weight loss outcomes of tirzepatide vs. semaglutide in people with obesity or overweight. While most participants lost 5% or more of their body weight, those taking tirzepatide experienced more significant weight loss at three, six, and 12 months of treatment—at the end of 12 months, those taking tirzepatide lost an average of 15% of their body weight, compared to around 8% on semaglutide.  

Zepbound and Wegovy were also recently studied in a head-to-head clinical trial to compare each drug’s weight loss potential in people without type 2 diabetes. The final study hasn’t been published yet, but preliminary reports show that Zepbound caused more weight loss overall. At the end of 72 weeks, people taking Zepbound lost about 20% of their body weight (roughly 50 pounds), and those taking Wegovy lost 13% of their weight (about 33 pounds). 

These results are somewhat similar to those in individual clinical trials on both tirzepatide and semaglutide:

• In a 2023 study, participants were given either tirzepatide (10 or 15 mg) or a placebo for 72 weeks. Those taking tirzepatide lost an average of 18.4% of their body weight, while those on the placebo lost 2.5%.

• One 2023 review looked at 10 studies involving 9,873 patients with both obesity and type 2 diabetes who took 5 mg, 10 mg, and 15 mg doses of tirzepatide and found evidence of significant weight loss at each dose strength. On average, participants taking tirzepatide lost about 20 pounds more than those in the placebo group.

• A 2024 study looked at the long-term results of semaglutide treatment in individuals with overweight or obesity without diabetes. Over 68 weeks, participants taking 2.4 mg of semaglutide (the maximum dose of Wegovy) lost an average of 27 pounds, compared to about five pounds in the placebo group. Additionally, roughly half of the participants on semaglutide experienced a 15% reduction in body weight.

• A 2023 review of randomized controlled trials involving 3,962 adults with obesity or overweight found that semaglutide reduced body weight, body mass index (BMI), and waist circumference, as well as improvements in blood pressure, cholesterol, and blood sugar levels compared to a placebo. Participants taking 2.4 mg of semaglutide lost an average of  11.8% of their body weight.

While the potential weight loss outcomes with both drugs are promising, Dr. Klein says it’s critical to remember that these medications aren’t a cure-all—they are most effective when combined with healthy lifestyle changes. In clinical trials, participants combined medication with a balanced, reduced-calorie diet (eating about 500 fewer calories per day) and about 150 minutes of moderate exercise each week. 

Tizepatide and semaglutide are also meant to be taken long-term. If you stop taking them or stop them too soon, your appetite and food cravings may return and you may gain back some or all of the weight you lost. 

In a 2022 study, participants on semaglutide lost 17.3% of their body weight over 68 weeks. One year after stopping the medication and lifestyle changes, participants regained about two-thirds of the weight they’d lost.

A 2023 study found that 670 adults lost an average of 20.9% of their weight on tirzepatide over 36 weeks. Those who switched to placebo regained 14%, while those who continued tirzepatide lost an additional 5.5%.

“The success of each medication can vary,” Dr. Klein says. “it depends on how well the patient partners with the medication, maintains lifestyle changes, and prevents weight regain.”

In addition, Kyle emphasizes the significance of a strong support system throughout treatment. “Everyone needs a solid support system,” he says. “The best support may come from a friend, a family member, or a spouse.”

He also notes that professional support from your healthcare provider can be invaluable in overcoming challenges and staying motivated. “It's important to know that you deserve support, and it's worth seeking until you find it,” he says.

Which is better, semaglutide or tirzepatide?

Studies suggest that people may lose more weight with tirzepatide than with semaglutide, but that fact alone doesn’t necessarily make one better than the other. Each person is unique, and many people have found success with either drug—online Wegovy reviews and Zepbound patient testimonials show promising outcomes with each medication. 

Determining which one is best for you depends on various factors, including your current health status, overall goals, insurance coverage, how well you tolerate the medication, and more. 

Both tirzepatide and semaglutide may cause similar side effects. The most commonly reported side effects of either medication are gastrointestinal (GI) complaints, but these tend to be mild and manageable and may go away the longer you take the medication. 

Dr. Klein points out that while their side effects are similar, she believes patient tolerance can vary greatly and neither medication is known to have more side effects than the other. 

"Patients can tolerate these medications the same or have completely different reactions to them,” she says. “I have patients who cannot tolerate Wegovy (semaglutide) but can tolerate Zepbound (tirzepatide), or, alternatively, they tolerate Wegovy but not Zepbound."

Some common side effects of tirzepatide include:

• Nausea

• Vomiting

• Diarrhea

• Constipation

• Abdominal pain

• Decreased appetite

• DIzziness

• Fatigue

• Indigestion/upset stomach

• Hair loss

• Injection site reactions (rash, itching)

Some common side effects of semaglutide may include:

• Nausea

• Vomiting

• Diarrhea

• Abdominal pain

• Constipation

• Headache

• Fatigue 

• Indigestion or heartburn

• Dizziness

• Bloating

Rare but serious side effects 

Both tirzepatide and semaglutide can cause more serious side effects, though these are rare. These include:

• Pancreatitis. Both medications may increase the risk for pancreatitis, or inflammation of the pancreas, though this may be more likely to occur in people with a history of pancreatitis or who have other risk factors.  

• Thyroid tumors. Both tirzepatide and semaglutide carry black box warnings about an increased risk of thyroid tumors, including a rare form of thyroid cancer (medullary thyroid carcinoma). 

• Gallbladder disease. GLP-1s may increase the risk of gallbladder inflammation or gallstones, potentially due to the slower digestion that occurs on these medications.

• Allergic reactions. Though rare, some people have reported severe allergic reactions (including anaphylaxis) with both tirzepatide and semaglutide.  

• Kidney problems. People with existing kidney issues may notice worsening symptoms while taking these medications. 

Who should not take tirzepatide or semaglutide?

Tirzepatide and semaglutide are generally safe, but they may not be suitable for everyone, including:

• People with a personal or family history of thyroid cancer or multiple endocrine neoplasia syndrome type 2 (MEN2)

• People with a personal or family history of pancreatitis 

• People with known hypersensitivity to any component of the medication 

• People who are pregnant, breastfeeding, and planning to become pregnant

Always consult a healthcare provider before starting a new medication. They can evaluate your individual and family health history, goals, and other medications to help determine if treatment with tirzepatide or semaglutide is right for you. 

The cost of weight loss medications can vary widely depending on insurance coverage, eligibility for savings programs, and other discounts. 

Many insurance plans do not cover GLP-1 medications for weight loss, even if they cover them for diabetes. Patients should check with their provider and explore savings programs if necessary. 

Here are some quick facts to know about the cost of each medication. 

Zepbound (tirzepatide) cost 

• The list price for Zepbound is $1086.37 per month before insurance or other savings. 

• If you have commercial insurance, you may be eligible for additional savings programs through Eli Lilly, the maker of Zepbound. The Zepbound Savings Card can lower the cost of Zepbound to just $25 for a one-month or three-month supply. Another cost-saving option is available through Ro and Lilly Direct, where you can access single-use vials of Zepbound (in either 2.5 mg or 5 mg doses) for $349-$499 each month. 

• If your insurance doesn’t cover Zepbound and you’re not eligible for savings programs, you may be able to offset your monthly costs with Zepbound coupons from online drug discount sites. 

Wegovy (semaglutide) cost

• The monthly list price for Wegovy is $1349.02 without insurance or discounts. You can also access Wegovy for $499 per month with Novo Nordisk’s new NovoCare Pharmacy offers.

• If you have commercial insurance and meet certain eligibility requirements, you may be able to access Wegovy for as little as $0 per 28-day supply with a Wegovy Savings Card, though this offer is subject to a maximum savings of $225 per box for up to 13 refills. If your insurance doesn’t cover Wegovy, you’re uninsured, or you pay for your prescription in cash, you may pay about $650 per month under the savings program. 

• Other programs may help offset the cost of Wegovy. For example, online drug discount sites may offer Wegovy coupons through select retail pharmacies. 

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Choosing the right medication is a personal decision you should make with the guidance of your healthcare provider. 

Here are some helpful questions to ask to help figure out whether semaglutide or tirzepatide is right for you:

• Am I a good candidate for weight loss medication?

• How do Zepbound and Wegovy compare in terms of effectiveness?

• Are there any factors that would make one medication a better choice than the other?

• What are the potential side effects and how do I manage them?

• Are there any other serious side effects or risks I should know about?

• How long will I need to take the medication?

• How much weight can I expect to lose, and when will I start to see results?

• How much does each medication cost?

• Are GLP-1s covered by my insurance?

• Am I eligible for discounts or savings programs to help with out-of-pocket costs?

Tirzepatide and semaglutide can both be effective treatments for weight loss. Which treatment is better for you and your unique needs depends on factors like your health status, goals, and more.

• While both tirzepatide and semaglutide share similar side effects and safety profiles, they are two distinct drugs that work in slightly different ways. Tirzepatide targets GLP-1 and GIP receptors, while semaglutide targets only GLP-1 receptors. 

• Research suggests that tirzepatide may lead to more weight loss than semaglutide. This may be due to its dual-action mechanism, but more research is needed to confirm this. 

• Common side effects of both medications include nausea, diarrhea, and vomiting. Side effects tend to be mild and manageable, and may go away over time. 

• Both medications can cost more than $1,000 per month. Insurance, discounts, and savings programs may help offset out-of-pocket costs. 

• Neither drug is meant to work in isolation. For optimal results, treatment with tirzepatide or semaglutide should be paired with a balanced, healthy diet and regular exercise.

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

March 14, 2025

Written by

Lianna Bass

Fact checked by

Ecler Ercole Jaqua, MD, MBA, DABOM

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About the medical reviewer

Ecler Ercole Jaqua, MD, MBA, DABOM

Ecler Ercole Jaqua, MD, MBA, DABOM, is the associate program director of the Loma Linda University Family Medicine Residency.