Weight Loss
22 min read
Written by Patricia Weiser, PharmD
Published: Apr 8, 2024
Medically Reviewed by Dr. Sheelu Bhatnagar
Trying to figure out the differences between Saxenda vs Mounjaro vs Zepbound? You’re not alone. Many people feel overwhelmed by all the weight loss medications out there. Learning about the options can help you talk with your healthcare provider about which medically supervised weight loss approach is right for you.
Two options gaining attention for their weight loss effectiveness are liraglutide and tirzepatide. If you haven’t heard of them, you may recognize their brand names. Liraglutide is sold under the brands Victoza for type 2 diabetes and Saxenda for weight loss. Similarly, tirzepatide is sold as the brands Mounjaro for type 2 diabetes and Zepbound for weight loss.
Keep reading this article for an in-depth look at Saxenda vs Mounjaro (aka Zepbound), including their costs, effectiveness for weight loss, dosage, side effects, how they work, and more.
Saxenda, Mounjaro, and Zepbound are brand-name prescription medications that are similar in some ways. For example, all 3 come as prefilled pens you use to give yourself weight loss injections. But these medications have differences too, including their indications, which are the specific uses the U.S. Food and Drug Administration (FDA) has approved each one to treat.
The FDA approved Saxenda (liraglutide) and Zepbound (tirzepatide) for long-term weight management alongside a reduced-calorie diet and increased exercise in adults with obesity or overweight who meet one of the following criteria:
Saxenda is also FDA-approved for use in children ages 12 years and older, if they meet one of the following criteria:
Unlike Saxenda, tirzepatide is not FDA-approved for children.
Zepbound and Mounjaro share the identical active ingredient of tirzepatide, but Mounjaro isn’t FDA-approved for weight loss. Instead, the FDA approves Mounjaro to lower blood sugar (glucose) in adults with type 2 diabetes, along with diet and exercise. Mounjaro is commonly used off-label for weight loss, which led to the drugmaker Eli Lilly coming out with Zepbound. Zepbound is FDA-approved for weight management in adults who meet the criteria noted above.
Substantial weight loss can occur while taking any one of these weight loss medications. Between Saxenda and Zepbound, most clinical trial results suggest that tirzepatide (Zepbound) leads to more weight loss than Saxenda (liraglutide), on average. While individual results vary, looking at the clinical trials details helps give you an idea of what to expect.
The primary clinical study for Saxenda compared the medication to a placebo (an injection that contained no active ingredient). Trial participants were overweight or obese adults who didn’t have type 2 diabetes and who followed a reduced-calorie diet and increased physical activity. After 56 weeks, the majority of participants who took a maximum daily dose of 3.0 milligrams of Saxenda lost 5 to 10% of their initial body weight. And more than a third of Saxenda participants experienced weight loss greater than 10% of their body weight. On average, Saxenda resulted in weight loss of about 8% of initial body weight.
Based on the average loss of 8% of body weight, someone with a starting body weight of 250 pounds can reasonably expect to experience a 20-pound weight loss with Saxenda.
A clinical trial of Zepbound also compared the medication to a placebo. Participants also followed a lower-calorie diet and began exercising more. After 72 weeks, over 85% of participants who took Zepbound lost 5% or more of their body weight. More than half of participants taking at least 10 milligrams of Zepbound weekly experienced a body weight reduction of 20% or more. On average, those taking the highest dose (15 milligrams weekly) of Zepbound lost 20.9% of their initial body weight.
Based on this average, a person with a starting body weight of 250 pounds can reasonably expect to experience a 52-pound weight loss with Zepbound.
Since Mounjaro and Zepbound use the same active ingredient, Mounjaro leads to weight loss and helps with blood sugar control. And losing weight may help improve long-term outcomes in people with type 2 diabetes. In clinical trials for Mounjaro, people with type 2 diabetes who took tirzepatide lost up to 13.9% of their starting body weight in 104 weeks.
If you’re not sure if Mounjaro or Zepbound is better for you, ask your healthcare provider if weight loss drugs are right for you.
Brand | Saxenda | Zepbound (Mounjaro) |
Drug class | GLP-1 agonist | Dual GLP-1 and GIP receptor agonist |
Active ingredient | Liraglutide | Tirzepatide |
Generic | None available | None available |
Form(s) | Liquid administered by injection | Liquid administered by injection |
Dosing | Starting dose: 0.6 mg injected subcutaneously each day After week 1: 1.2 mg each day After week 2: 1.8 mg each day After week 3: 2.4 mg each day After week 4: 3.0 mg each day Maintenance dose: 3.0 mg each day Maximum dose: 3.0 mg each day | Starting dose: 2.5 mg injected subcutaneously once a week After week 4: 5 mg once a week Can be increased in 2.5 mg increments every 4 weeks if needed Recommended maintenance doses: 5 mg, 10 mg, or 15 mg once a week Maximum dose: 15 mg once a week |
Frequency | Daily subcutaneous injection | Weekly subcutaneous injection |
Approved for | Weight loss for: Adults with body mass index (BMI) at or above 30 Adults with a BMI at or above 27 with a weight-related health condition Children 12 or older with a BMI that converts to an adult BMI of 30 or greater Should be used with a reduced-calorie meal plan and increased physical activity | Zepbound Weight loss in: Adults with a BMI at or above 30 Adults with a BMI at or above 27 with a weight-related health condition Should be used with a reduced-calorie meal plan and increased physical activity Mounjaro To improve blood sugar (glucose) in: Adults with type 2 diabetes Should be used with diet and exercise |
Retail Cost | $1,349 for a 28-day supply* | Zepbound $1,113 for a 28-day supply* Mounjaro $1,069 for a 28-day supply* |
Common side effects | Nausea Diarrhea Stomach pain Upset stomach Dizziness Bloating Gas Fatigue Headache Vomiting Constipation Heartburn Runny nose Sore throat | Zepbound Nausea Diarrhea Vomiting Constipation stomach pain Indigestion Injection site reactions Feeling tired Belching Hair loss Heartburn Mounjaro Nausea Diarrhea Decreased appetite Vomiting Constipation Indigestion Stomach pain |
Serious side effects | Allergic reaction Inflammation of the pancreas (pancreatitis) Gallbladder problems Low blood sugar (hypoglycemia) Kidney problems Changes in vision Increased heart rate Suicidal behavior or thoughts | Zepbound Allergic reactionInflammation of the pancreas (pancreatitis) Gallbladder problems Low blood sugar (hypoglycemia) Kidney problems Changes in vision Severe stomach problems Mounjaro Allergic reaction Inflammation of the pancreas (pancreatitis) Gallbladder problems Low blood sugar (hypoglycemia) Kidney problems Changes in vision Severe stomach problems |
Boxed warning | Risk of thyroid tumors, including cancer See full prescribing information for complete boxed warning. | Risk of thyroid tumors, including cancer See full prescribing information for complete boxed warning. |
Weight loss potential | Average 8% reduction in body weight (data) | Zepbound Average 20.9% reduction in body weight on the highest dose (data) Mounjaro Up to 13.9% reduction in body weight for those with type 2 diabetes (data) |
* Prices according to manufacturer websites as of March 2024.
Mounjaro and Zepbound contain the same active ingredient tirzepatide, but Mounjaro is FDA-approved for type 2 diabetes and Zepbound for weight loss.
Similarly, Saxenda’s counterpart, Victoza, contains the same active ingredient (liraglutide) but has different uses. The FDA approves Victoza, along with diet and exercise, for people with type 2 diabetes who meet certain criteria.
Weight loss is not an FDA-approved indication for Victoza. However, Victoza may promote weight loss in people with type 2 diabetes as an additional benefit.
In a separate Mounjaro clinical trial and Victoza clinical trial, researchers studied how well each medication lowered blood sugar levels compared to other diabetes medications. In these studies, both Victoza and Mounjaro were found to be highly effective for lowering blood sugar levels. But Mounjaro led to a greater improvement in a shorter amount of time.
The table below highlights a few key differences of Victoza vs Mounjaro for type 2 diabetes.
Brand | Victoza | Mounjaro |
Active ingredient | Liraglutide | Tirzepatide |
Frequency | Daily subcutaneous injection | Weekly subcutaneous injection |
Approved for | To improve blood sugar (glucose) in: Adults with type 2 diabetes Children 10 or older with type 2 diabetes To reduce risk of heart complications in: Adults with type 2 diabetes and heart disease | To improve blood sugar (glucose) in: Adults with type 2 diabetes Should be used with diet and exercise |
Retail Cost | $815 for a 28-day supply* | $1,069 for a 28-day supply* |
Saxenda and Moujaro work in similar ways. This section looks at how these medications work for promoting weight loss and managing blood sugar levels.
Saxenda contains the active ingredient liraglutide. Liraglutide belongs to a class of medications known as glucagon-like peptide-1 receptor agonists (GLP-1s). Like other receptor agonist medications in this class, Saxenda works by mimicking GLP-1 to help replace or enhance its effects.
Mounjaro and Zepbound contain the same active ingredient, tirzepatide. Tirzepatide mimics 2 peptides in the body: GLP-1 and glucose-dependent insulinotropic peptide (GIP).
When these peptides activate certain receptors in the body, changes occur in your digestive and metabolic processes that promote weight loss and better glucose regulation.
Both liraglutide and tirzepatide work for weight loss by altering the normal digestive process, increasing the sensation of feeling full and slowing the passing of food through the gut. While using liraglutide or tirzepatide, a person’s appetite decreases, which helps promote weight loss.
Liraglutide and tirzepatide work to lower blood sugar by mimicking GLP-1 (liraglutide) and GLP-1/GIP peptides (tirzepatide). In the body, these peptides communicate with the pancreas, the organ that makes insulin. When blood sugar rises, GLP-1 and GIP tell the pancreas to release insulin into the blood; this, in turn, helps lower blood sugar. The GLP-1 and GLP-1/GIP receptor agonist medications act exactly like these peptides, ultimately leading to lower blood sugar levels.
Yes. As long as a licensed medical professional confirms that the switch is safe and appropriate for you. Also, when switching from one medication to another, a dosing adjustment may be needed to limit side effects caused by switching to a stronger GLP-1 or GLP-1/GIP receptor agonist.
No. The FDA warns against using more than one GLP-1 or GLP-1/GIP receptor agonist medication at the same time. Combining medications may increase the risk of serious side effects.
Before starting any medication, it’s essential to weigh the risks and benefits. This section highlights some of the side effects and risks to consider before you take Saxenda, Mounjaro, or Zepbound.
Saxenda, Mounjaro, and Zepbound may cause similar side effects. Typically, side effects are mild and go away within a few weeks as the body adjusts to the medication. Side effects may also be more noticeable after you increase your dose.
Since tirzepatide is stronger than liraglutide, side effects are more likely to occur and may be more bothersome with tirzepatide compared to liraglutide. But, as with all medications, individual experience varies.
Common side effects of liraglutide and tirzepatide include:
Rare but serious side effects of these medications may include allergic reactions, pancreatitis, low blood sugar if taken with insulin or certain diabetes medications, or kidney problems. For a full list of possible side effects, see the prescribing information for Saxenda, Mounjaro, and Zepbound.
The FDA requires boxed warnings (aka black box warnings) on the label information (aka prescribing information) for all GLP-1 and GLP-1/GIP receptor agonist medications. This is because thyroid tumors were observed in mice and rats when researchers were testing these medications in animal studies. It isn’t known if this risk applies to humans, but as a precaution, the FDA recommends against using these medications in anyone with a personal or family history of medullary thyroid carcinoma (a type of thyroid cancer) or multiple endocrine neoplasia syndrome type 2 (MEN2).
People with a known hypersensitivity to tirzepatide or liraglutide or who are pregnant or want to get pregnant should also avoid the medications.
The retail cost for a 4-week supply (as of the time of this writing) for Zepbound vs Saxenda vs Mounjaro according to drugs.com are:
These prices represent the out-of-pocket price of the products without insurance. You may pay less if your insurance plan covers Saxenda, Mounjaro, or Zepbound. Also, the manufacturers of Saxenda, Mounjaro, and Zepbound offer savings cards that may help you get discounted medication.
Saxenda, Mounjaro, and Zepbound all work to help people lose weight when used alongside a lower-calorie diet and increased exercise.
For individuals with type 2 diabetes, Mounjaro is proven to lower blood sugar and promote weight loss. And even moderate weight loss can improve long-term health for people with type 2 diabetes.
If you’re interested in weight loss but you don’t have type 2 diabetes, Saxenda or Zepbound may be a better fit. Of the 2, Zepbound is the stronger medication based on a comparison of clinical trial results. But individual results can vary, and some people may not be able to tolerate the higher doses necessary to see optimal weight loss results.
Choosing a weight-loss medication is a decision that’s made between you and a healthcare provider after discussing your medical history, other medications, and other unique factors. They will help determine if one of these medications is safe and appropriate and aligns with your health needs and goals.
While Saxenda and Zepbound can be effective weight loss tools, it’s important to remember they’re only one part of a comprehensive plan for reaching and maintaining a healthy weight. A well-rounded approach involves other aspects, such as diet changes, boosting physical activity, addressing related mental health concerns, and building a strong community for support. Find a weight loss provider on Klarity and start your weight loss journey today.
The information provided in this article is for educational purposes only and should not be construed as medical advice. Always seek the guidance of a qualified healthcare professional with any questions or concerns you have regarding your health.
How we reviewed this article: This article goes through rigorous fact-checking by a team of medical reviewers. 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 author.
Get free, credible health and wellness tips from Klarity
Subscribe to our blog for the latest insights and advice—totally free! No spam, and you can unsubscribe at any time.