Wegovy (Semaglutide) has been the go-to weight loss medication since its introduction in June 2021. Still, with the approval of Tirzepatide for weight loss under the brand name Zepbound on November 8, 2023, questions have been asked about which is more effective between Zepbound and Wegovy.

Both medications are great for weight management but have different active ingredients: Wegovy contains semaglutide, while Zepbound is made of tirzepatide. Research suggests that tirzepatide may lead to more weight loss, but this doesn't always mean it is a better option. Factors like side effects, contraindications, interactions, budget, and more must be considered to determine the best choice.

Here, we will compare these two weight loss medications regarding their working mechanisms, efficacy, safety profiles, dosage, and costs to help you make an informed decision for weight management.

Key Facts

  • While Wegovy (Semaglutide) is a GLP-1 agonist, Zepbound (Tirzepatide) is a dual agonist medication that activates both GLP-1 and GIP hormone receptors.

  • Both Wegovy and Zepbound are effective for weight management. However, research found that tirzepatide triggered up to 17.8% weight loss compared to semaglutide's 12.4%.
  • Zepbound and Mounjaro share the same active ingredient (tirzepatide), while Ozempic and Wegovy share another different active ingredient (semaglutide). However, Mounjaro and Ozempic are not approved as weight-loss medications. They are approved for type 2 diabetes management.
  • Zepbound and Wegovy are approved for weight loss in adults with a BMI of at least 30 or a BMI of 27 with weight-related comorbidity, like high blood pressure, type 2 diabetes, or cardiovascular disease.
  • The best medication for weight loss depends on the individual unique health profile, drug tolerance, side effects, and lifestyle. Experts suggest that these medicines shouldn't be used as a sole weight loss solution but should be part of a comprehensive management plan, including healthy diets and exercise.

How Do Zepbound and Wegovy Compare?

Wegovy and Zepbound are both used to treat overweight or obese people with one or more weight-related comorbidities, but the medications are not exactly the same. Let's find out how.

Approved Usage

Both Zepbound (tirzepatide) and Wegovy (semaglutide) are approved by the Food and Drug Administration (FDA) for weight management.

Wegovy Approved Usage:

Semaglutide was introduced in 2012 by a team of researchers at Novo Nordisk as a once-weekly diabetes therapy - a longer-acting alternative to liraglutide. It was given the brand name Ozempic. In 2017, the FDA approved the injectable version of Ozempic for diabetes management. However, in clinical practice, Ozempic (semaglutide) not only manages type 2 diabetes but also has weight loss effects. This inspired the FDA approval of semaglutide for weight loss in 2021 under a different brand name: Wegovy.

Zepbound Approved Usage:

Tirzepatide was approved for type 2 diabetes treatment as "Mounjaro" in May 2022. However, besides controlling blood sugar levels, Mounjaro also recorded tremendous success in weight management. In November 2023, the FDA approved tirzepatide for weight loss under another brand named "Zepbound."

Working Mechanism

How Wegovy Works:

Semaglutide, the active ingredient in Wegovy, lowers blood sugar by activating the glucagon-like peptide-1 (GLP-1) receptor; it mimics the action of a hormone called GLP-1. Your stomach naturally releases this hormone in response to food ingestion.

"It is from a group of drugs known as the GLP-1 analogs," says Dr. Sophie, an occupational health physician. "...What you actually want to know is it makes you less hungry and more easily full. So, you end up eating less and losing the weight," she added.

Semaglutide also directly affects the hypothalamus, an area of the brain that controls appetite and influences eating decisions. The medication increases satiety and makes you feel fuller by slowing down stomach emptying. This chain of actions will make you eat less, eat less often, and lose weight.

How Zepbound Works:

Unlike Wegovy, which activates only the GLP-1 receptor, Zepbound is a dual-agonist medication. Its active ingredient, tirzepatide, activates both glucagon-like peptide-1 (GLP-1) and glucose-dependant insulinotropic polypeptide (GIP) hormone receptors.

Tirzepatide enhances glucose-stimulated insulin secretion, delays stomach emptying, decreases plasma glucagon levels, and reduces body weight (by activating anorexigenic pathways in the brain to suppress appetite).

"Zepbound not only targets GLP-1 receptors to boost GLP levels; it also boosts a second hormone called GIP," says Christopher McGowan, MD - Founder and CEO of True You Weight Loss. "GIP regulates weight through receptors in the brain and fat cells. The actions of GLP-1 and GIP are synergistic, boosting each other's effects," he added.

Dosage and Duration of Action

Wegovy Dosage and Duration of Action:

Wegovy (semaglutide) is a long-acting, once-weekly injection. It is administered subcutaneously (under the skin, preferably the belly fat).

The medication comes in 5 different dose strengths. The starting dose is 0.25 mg, and you will gradually increase your dose every month. Your doctor can select either 1.7 or 2.4 mg for your maintenance dose.

Your Wegovy dosing schedule may look like this:

  • Month 1 (Weeks 1-4): 0.25mg per week
  • Month 2 (Weeks 5-8): 0.5mg per week
  • Month 3 (Weeks 9-12): 1mg per week
  • Month 4 (Weeks 13-16): 1.7mg per week
  • Month 5 (Week 17 and onward): 2.4mg weekly.

Zepbound Dosage and Duration of Action:

Zepbound is also a once-weekly injection, although it is being tested as a once-daily injection; hence, it may be used once daily in the future. The medication is administered subcutaneously (under the skin, preferably the belly fat).

The recommended starting dosage of Zepbound is 2.5 mg, injected subcutaneously once weekly. After the first four weeks, your doctor may increase the dosage to 5 mg. The subsequent doses may be increased in 2.5 mg increments after at least four weeks. The recommended maintenance dosages of Zepbound in adults are 5 mg, 10 mg, or 15 mg (maximum dose).

Side Effects

Wegovy and Zepbound present similar side effects, which are mainly gastrointestinal. Note that both medications come with boxed warnings regarding thyroid C-cell tumor risks.

Some common side effects of Wegovy and Zepbound include,

  • Nausea
  • Vomiting
  • Heartburn
  • Belching
  • Diarrhea
  • Constipation
  • Stomach (abdominal) pain
  • Indigestion
  • Injection site reactions
  • Fatigue
  • Allergic reactions

There are also rare reports of some severe side effects like vision changes, pancreatitis, kidney failure, gallbladder issues, severe allergic reactions, and suicidal thoughts.

Cost

Although Zepbound causes more weight loss than Wegovy, it is relatively less expensive, too, which is why its introduction is deemed a "relief" for overweight and obese people who struggle to afford Wegovy. Research has shown that Tirzepatide provides better value for money than semaglutide for weight reduction.

Wegovy Cost:

Wegovy is priced at around $1,349 for a month's supply.

Zepbound Cost:

Zepbound, on the other hand, costs around $1060 for a month's supply, about 21.4% lower than Wegovy's price.

Limitation of Usage

Who Cannot Use Wegovy?

  • Pregnancy: Wegovy is not recommended for pregnant women
  • Age: Wegovy is FDA-approved for patients 12 or older with an initial BMI at the 95th percentile or greater standardized for age and sex (obesity).
  • Contraindication: Wegovy is not prescribed for patients with a personal or family history of Medullary thyroid cancer (MTC). It is also not used for those with Multiple endocrine neoplasia 2 (MEN2) and in patients who are allergic to semaglutide.
  • Co-administration and Interactions: Wegovy interacts with sulfonylurea or insulin and may cause severe hypoglycemia when taken together. The active ingredient in Wegovy is semaglutide. So, it should not be coadministered with other semaglutide-containing products or with any GLP-1 receptor agonist.

Who Cannot Use Zepbound?

  • Pregnancy: Just like Wegovy, Zepbound may harm unborn babies and is not recommended for pregnant women.
  • Age: Zepbound is prescribed for adults. Its effectiveness for teens is yet to be determined.
  • Contraindication: It is not advisable to use Zepbound for someone with a personal or family history of MTC. Zepbound is also not prescribed for someone with MEN 2 or who has had a severe allergic reaction to tirzepatide or any of the ingredients in Zepbound.
  • Co-administration and Interactions: Zepbound contains tirzepatide as an active ingredient and should not be used with other tirzepatide-containing products or any GLP-1 receptor agonists. Also, taking Zepbound while on sulfonylurea or insulin may cause hypoglycemia.

Which is Best for Weight Management Between Wegovy and Zepbound?

Both medications are effective for weight management, but research has shown that Zepbound triggers more weight loss than Wegovy.

However, the best option between the two doesn't only depend on how much weight you lose on the drug but on many other factors, including side effects, contraindications, interactions, budget, etc.

For instance, while you may lose more weight on Zepbound, it may not be your best option if you have had a severe allergic reaction to tirzepatide. On the other hand, Wegovy, being more expensive than Zepbound, may not be the best for you if you can't afford it in the long run.

So, the best choice between Zepbound and Wegovy primarily depends on personal circumstances. That's why you must work closely with your doctor to ascertain the most suitable medication to kick-start your weight loss journey.

Remember, these drugs are a tool to help with weight loss. So, they must be combined with healthy lifestyle and diet choices for the best result.

Conclusion

Both Zepbound and Wegovy are good choices for people fighting obesity. They share similar side effects and contraindications. The only clear-cut difference is their working mechanism: Wegovy (semaglutide) is a GLP-1 agonist, but Zepbound (tirzepatide) is a dual agonist medication that activates GLP-1 and GIP hormone receptors. Another striking difference is their dosing schedules. While Wegovy starts from 0.25mg and increases every four weeks until a maintenance dose of 2.4mg is reached, Zepbound's starting dose is 2.5mg, which can be increased to a maximum dose of 15mg (for maintenance).

Before opting for any of these drugs, remember weight management is not something you do with just medications. You need a comprehensive plan that includes healthy diets and lifestyles. You also need a medication most suitable for your long-term budget and health conditions. Your doctor can help you decide which one is right for you based on your uniqueness and what you want to achieve.

Sources

At Diabetic Me, we are committed to delivering information that is precise, accurate, and pertinent. Our articles are supported by verified data from research papers, prestigious organizations, academic institutions, and medical associations to guarantee the integrity and relevance of the information we provide. You can learn more about our process and team on the about us page.

  1. Drugbank Online Tirzepatide
  2. Wegovy Wegovy® Dosing Schedule
  3. Zepbound Lilly Your weekly Zepbound routine
  4. National Library of Medicine Tirzepatide versus semaglutide for weight loss in patients with type 2 diabetes mellitus: A value for money analysis
  5. LinkedIn Dr Sophie A. - Doctor - Occupational Health Physician, GP trainee. Founder of Bolly Bhangra Fit dance company Cambridge.
  6. LinkedIn Christopher McGowan

About the Author

Ely Fornoville

Hi, I'm Ely Fornoville, and I am the founder of Diabetic Me. Being a type 1 diabetic since 1996, I developed a passion to help people learn more about diabetes. I write about diabetes and share stories from other diabetics around the world. I currently use a Medtronic Guardian 4 CGM and a MiniMed 780G insulin pump with Humalog insulin.

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