What is the mechanism of action of Tirzepatide (Mounjaro)?

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Last updated: April 25, 2025View editorial policy

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From the Guidelines

Tirzepatide is the most effective medication for obesity management in adults, with a mean weight loss of 20.9% at 72-week follow-up, and should be considered as the first-line treatment for obesity. The medication is a synthetic peptide with dual-hormone agonistic activity at the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide receptor, dosed subcutaneously once weekly 1. Some key points about tirzepatide include:

  • It was FDA approved for treatment of obesity in November 2023 1
  • A recent meta-analysis of RCTs reported that 15 mg weekly of tirzepatide was associated with greater weight loss compared with 2.4 mg weekly of subcutaneous semaglutide and 3 mg daily of subcutaneous liraglutide 1
  • The most common side effects of tirzepatide are not explicitly mentioned in the provided evidence, but it is known that GLP-1 receptor agonists can cause nausea, vomiting, diarrhea, and constipation
  • The medication should be stored in the refrigerator and avoided freezing, and patients should follow proper injection technique
  • Tirzepatide represents a significant advancement in metabolic disease treatment due to its effectiveness in improving glycemic control and producing substantial weight loss, often superior to other GLP-1 receptor agonists like semaglutide 1. The dosing of tirzepatide typically starts at 2.5mg and gradually increases to a maintenance dose of 5mg, 10mg, or 15mg based on patient response and tolerability. Overall, tirzepatide is a highly effective medication for obesity management and should be considered as a first-line treatment option.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Overview of Tirzepatide

  • Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist, approved for the treatment of adults with type 2 diabetes mellitus (T2DM) and chronic weight management 2, 3, 4, 5, 6.
  • It is administered as a once-weekly injection and has shown efficacy in reducing HbA1c levels and body weight in patients with T2DM 2, 3, 4, 5, 6.

Efficacy of Tirzepatide

  • Studies have demonstrated that tirzepatide is effective in reducing HbA1c levels, with mean reductions ranging from 1.02% to 3.02% 2, 4, 5, 6.
  • Tirzepatide has also been shown to result in significant weight loss, with mean reductions ranging from 7.3 kg to 8.47 kg 2, 4, 5, 6.
  • The efficacy of tirzepatide has been compared to other glucose-lowering therapies, including placebo, semaglutide, insulin degludec, and insulin glargine, and has been found to be superior in reducing HbA1c levels and body weight 3, 4, 5.

Safety of Tirzepatide

  • The safety profile of tirzepatide has been evaluated in several studies, and has been found to be generally acceptable 4, 5, 6.
  • Common adverse events associated with tirzepatide include gastrointestinal events such as nausea, vomiting, and diarrhea 3, 4, 5.
  • The incidence of hypoglycemia with tirzepatide has been found to be similar to that of placebo and lower than that of basal insulin regimens 4, 5.
  • Serious adverse events and mortality have been found to be low with tirzepatide treatment 4, 5, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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