Tirzepatide vs. Dulaglutide as Weight Loss Drugs

Tirzepatide and dulaglutide are both injectable medications that are used to treat type 2 diabetes and are safe for the prevention of diabetes and weight loss.

Tirzepatide and dulaglutide are both injectable medications that are used to treat type 2 diabetes, and are safe for use in pre-diabetics and non-diabetics for the prevention of diabetes and weight loss. Both medications work by helping the body to better use the insulin it produces, and can help to lower blood sugar levels. However, there are some key differences between the two medications, and it is important for patients to understand these differences when deciding which medication is right for them.

Mechanism of Action

Dulaglutide is a GLP-1 receptor agonist, while tirzepatide is both a GIP receptor agonist AND a GLP-1 receptor agonist. GLP-1 and GIP are molecules that are both known to help promote insulin release to help lower blood sugar, slow the emptying of the stomach, and decrease the production of glucagon, the hormone that tells your liver to make more blood sugar. Thus, tirzepatide is a combo drug that may pack more of a punch for reducing blood sugar and helping support weight control or weight loss

Administration of the Drugs 

Both medications are administered subcutaneously as an injectable. Dulaglutide is administered once per week in doses ranging from 0.75 mg to 4.5 mg. Tirzepatide is also administered once per week in doses ranging from 2.5 mg to 15 mg. 

Tirzepatide and Dulaglutide as an injectable



Side Effects of the Drugs 

According to the manufacturer’s website, the most common side effects of tirzepatide are nausea, diarrhea, decreased appetite, vomiting, constipation, and abdominal pain. Other less common, but serious side effects include low blood sugar, inflammation of the pancreas, kidney issues, allergic reactions, vision changes, and gallbladder problems. 


The manufacturer of dulaglutide reports very similar side effects. Both medications carry a small risk for the development of medullary thyroid cancer, and are contraindicated in patients predisposed to this type of cancer (examples: those with the genetic condition, MEN2, or a personal or family history of medullary thyroid cancer).


Tirzepatide and Dulaglutide side effects


Efficacy Level of Both Drugs 

Research studies directly comparing the efficacy of tirzepatide versus dulaglutide that can be generalized to the US population are still needed to fully understand how these two medications differ in their ability to lower patients’ hemoglobin A1c and promote weight loss. 


However, studies exist comparing tirzepatide to a drug similar to dulaglutide, semaglutide. In a randomized trial published in the New England Journal of Medicine, 1,879 adult patients with type 2 diabetes were assigned to once-weekly injections of either tirzepatide (at 5 mg, 10 mg, or 15 mg) or semaglutide 1 mg for 40 weeks. 


They found that patients on tirzepatide at all three doses had a larger improvement in their hemoglobin A1c and a bigger reduction in body weight. For example, the tirzepatide 15 mg group lost 11.2 kg, versus the semaglutide group, who lost 5.7 kg. That is nearly a 2x difference! Even at the lowest dosage, tirzepatide was found to be superior for both outcome measures. 


A 2018 review article comparing GLP-1 receptor agonists reported that, in studies, semaglutide 1 mg once weekly resulted in a mean weight loss from 4.53 to 6.5 kg, while dulaglutide at 1.5 mg once weekly resulted in a mean weight loss from 0.87 to 3.03 kg. With the results of these two studies, we can extrapolate that tirzepatide may lead to greater weight loss than dulaglutide. 


Conclusion

Overall, tirzepatide and dulaglutide are both effective options for treating and preventing type 2 diabetes, but they have some important differences. Both carry similar side effect profiles, but have a slightly different mechanism of action. Patients should discuss the pros and cons of each medication with their healthcare provider to determine which medication is the best fit for their individual needs. 

Mochi Health Can Help You Explore These Medications

If you would like to speak to a physician who specializes in Obesity Medicine with expertise in prescribing these medications, Mochi Health can help. Our providers can help explain the details of medications on the market like those listed above, and can help determine if one of these medications could be a safe and effective option for you if you are needing assistance with weight loss or management of type 2 diabetes. We are on your side at Mochi Health and cannot wait to meet you. Learn more here

References:

  1. Dungan K, DeSantis A. Glucagon-like peptide 1-based therapies for the treatment of type 2 diabetes mellitus. Post TW, ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com. Accessed March 23, 2021.
  2. Frías JP, Davies MJ, Rosenstock J, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021;385(6):503-515. doi:10.1056/NEJMoa2107519
  3. Gentilella R, Pechtner V, Corcos A, Consoli A. Glucagon-like peptide-1 receptor agonists in type 2 diabetes treatment: are they all the same?. Diabetes Metab Res Rev. 2019;35(1):e3070. doi:10.1002/dmrr.3070

Eva Shelton, M.D.

Harvard Medical School, Brigham and Women's Hospital

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