Tirzepatide: What the Clinical Trials Show

Tirzepatide: What the Clinical Trials Show

Tirzepatide is one of the medications our licensed physicians may consider when evaluating a patient for an appetite programme. This article summarises the key findings from the SURMOUNT-1 Phase 3 clinical trial, which forms part of the evidence base supporting the FDA approval of tirzepatide for chronic weight management. Individual results vary.

The SURMOUNT-1 Trial: Background

SURMOUNT-1 was a randomised, double-blind, placebo-controlled Phase 3 trial evaluating tirzepatide in adults with obesity or overweight. It was published in the New England Journal of Medicine in 2022:

Jastreboff AM, Aronne LJ, Ahmad NN, et al. "Tirzepatide Once Weekly for the Treatment of Obesity." New England Journal of Medicine. 2022;387:205–216.
https://www.nejm.org/doi/10.1056/NEJMoa2206038

Who Was in the Trial?

SURMOUNT-1 enrolled 2,539 adults with a BMI of 30 or greater, or a BMI of 27 or greater with at least one weight-related comorbidity. Participants with type 2 diabetes were excluded. All participants received lifestyle counselling — a reduced-calorie diet and increased physical activity guidance — throughout the 72-week study period.

What the Trial Measured

The co-primary endpoints were: (1) percentage change in body weight from baseline to week 72, and (2) the proportion of participants achieving at least 5% weight reduction. The trial tested three doses of tirzepatide: 5 mg, 10 mg, and 15 mg, each administered once weekly via subcutaneous injection.

What the Trial Found

As reported in Jastreboff et al. (2022), mean weight reductions from baseline at week 72 were as follows. Individual results vary.

  • Tirzepatide 5 mg: mean weight reduction of 15.0%
  • Tirzepatide 10 mg: mean weight reduction of 19.5%
  • Tirzepatide 15 mg: mean weight reduction of 20.9%
  • Placebo: mean weight reduction of 3.1%

Proportion achieving ≥5% weight reduction (as reported in Jastreboff et al., 2022). Individual results vary.

  • Tirzepatide 5 mg: 85%
  • Tirzepatide 10 mg: 89%
  • Tirzepatide 15 mg: 91%
  • Placebo: 35%

All figures cited above are taken directly from Jastreboff et al., NEJM, 2022. Individual results vary.

What Makes Tirzepatide Different

Unlike semaglutide, which acts solely on the GLP-1 receptor, tirzepatide is a dual agonist that activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. GIP is another incretin hormone involved in glucose metabolism and fat storage regulation. The dual mechanism is believed to contribute to the weight loss outcomes observed in SURMOUNT-1, though the relative contribution of each receptor pathway is still an area of ongoing research.

FDA Approval

The FDA approved tirzepatide (brand name Zepbound) for chronic weight management based on data including the SURMOUNT programme. The approval is referenced in the FDA press release: FDA Approves New Medication for Chronic Weight Management.

What This Means for Our Programme

A licensed physician at Bunny will determine whether tirzepatide is medically appropriate for you — and at what dose — based on your individual health profile. Tirzepatide is not suitable for everyone, and the decision rests with your doctor, not a quiz or a default protocol.

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All medical decisions are made solely by licensed healthcare professionals. Medications are prescribed only when medically necessary. GLP-1 medications are not suitable for everyone. Results may vary.

Results vary. Clinical trial results apply only to the FDA-approved branded medication specifically identified and do not apply to compounded medications. All medications must be prescribed by a licensed provider based on medical necessity.