Medically reviewed on November 19, 2023 by Morgan Spicer, Medical Communications Manager. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Obesity can result in many serious health complications such as stroke, diabetes, or heart disease.  In the United States, obesity affects nearly 42% of adults and nearly 20% of children, costing over $146 billion in annual healthcare costs.  While many people are aware of prevention and treatment methods for obesity, there are many challenges and existing disparities that make weight management difficult.  In recent years, there has been an increase in the utilization of weight loss medications in combination with other lifestyle changes. Research shows that combining these efforts may result in significant weight loss. 
Tirzepatide is an injectable medication that treats type 2 diabetes and has been recently approved by the FDA for weight loss. [1,5] Tirzepatide works by activating a pathway that increases insulin levels in the body, which in turn causes glucose levels to decrease. Tirzepatide may also cause a decreased appetite. Common brand names of tirzepatide include Mounjaro® for type 2 diabetes and Zepbound® for weight loss. [1,6]
Tirzepatide is now approved for weight loss by the FDA.  On November 8 2023, the FDA approved tirzepatide for weight loss under the brand name Zepbound®.  The medication is expected to be available in the U.S. by the end of 2023 at a list price of $1,059.87. After insurance, the medication may be available for as low as $25 for a one-to-three-month prescription. 
As of early November 2023, a new weight loss drug has been approved for those who are obese or overweight with at least one weight-related condition such as high blood pressure, high cholesterol, or type 2 diabetes.  This new obesity drug is a once-weekly injection called Zepbound®. The active ingredient is tirzepatide, the same active compound as the diabetes drug Mounjaro®. [6,7] Zepbound® works by activating glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) hormone receptors. [1,6,7] These are hormones that are made in the intestine and play important roles in how the body manages and reacts to insulin, glucose, digestion, and satiety (how full you feel after eating). [8-9] Zepbound® is the first weight loss treatment to be FDA-approved that activates both GIP and GLP-1 receptors. 
Zepbound® (tirzepatide) will soon be available for weight loss in six doses, including 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. [1,7] Zepbound® is administered as an injection under the skin of the stomach, thigh, or upper arm. The medication is administered once per week at any time of the day.  If you are prescribed this medication, your healthcare provider can speak to you about what dose is right for you.
So what is the difference between Mounjaro® and Zepbound®? Both drugs have the same active ingredient, tirzepatide, which increases insulin sensitivity, decreases appetite, and slows digestion.  The main difference between the two is that Zepbound® is FDA-approved for weight loss, while Mounjaro® is FDA-approved for type 2 diabetes. [1,6,7] Some providers have prescribed Mounjaro(R) off-label for weight loss, and may continue to do so.  Off-label use refers to a drug being prescribed for a purpose other than what the FDA has approved it for.  One key thing to note is that insurance may not cover medications prescribed off-label, so the recent approval of Zepbound® is likely to pave the way for insurance coverage and increased prescriptions. 
Recent studies have highlighted many health benefits as a result of Zepbound® use. These studies found that in combination with a reduced-calorie diet and increased physical activity, Zepbound® is an effective drug for chronic weight management. [1,7] Weight loss was observed in patients who received all studied dose levels (5 mg, 10 mg, and 15 mg). [1,7] According to one study, adults taking the highest dose of Zepbound® for 72 weeks lost on average 48 lb, while those taking the lowest dose for 72 weeks lost on average 34 lb.  In addition to weight loss, observed benefits of Zepbound® include improved cholesterol levels, reduced blood pressure, and improved glycemic control. [1,7]
Zepbound® has been shown to cause some side effects in patients who take it, including nausea, vomiting, diarrhea, constipation, abdominal discomfort, fatigue, injection site reactions, allergic reactions, burping, hair loss, and gastroesophageal reflux (acid reflux). [1,7] Research also shows that Zepbound® causes thyroid C-cell tumors in rats; however, it is unknown if the drug causes such tumors in humans (though no studies have observed this effect as of yet).  Additionally, Zepbound® has not been studied in patients with a history of pancreatitis or severe gastrointestinal disease. Those with underlying health conditions or taking certain medications, such as Mounjaro® or GLP-1s, may not be suitable for Zepbound®.  If prescribed this medication, it is recommended to speak with your healthcare provider about all of the benefits and risks of Zepbound® prior to use. Learn how you can manage some weight loss drug side effects.
It’s estimated that Zepbound® will be available in the U.S. by the end of 2023. [1,7] Zepbound® has been approved for those who are obese or overweight with at least one weight-related condition. [1,7] If you are interested in tirzepatide for weight loss, it is recommended to connect with your healthcare provider to discuss your options. Depending on your health status, you may qualify for Zepbound® or Mounjaro®.
Those who are overweight or obese often have higher risks of heart disease, diabetes, and stroke.  Research shows that even a 5% reduction in body weight may significantly improve health outcomes and reduce the risk of various conditions.  Everlywell is here to support you on your health and wellness journey with a collection of easy-to-use at-home lab tests. Additionally, our Weight Care+ program provides you with access to a broad network of board-certified clinicians who can help with weight loss. By enrolling in our online weight loss program, you’ll get one-on-one virtual visits with licensed clinicians, healthy lifestyle content, and access to GLP-1 receptor agonist prescriptions for qualified candidates.