Obesity and type 2 diabetes mellitus (T2DM) represent major public health concerns in the aging community. Tirzepatide, a novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist recently approved for the treatment of T2DM and obesity has been shown to be effective at reducing weight, improving markers of T2DM control, and improving cardiovascular health. Utilization of tirzepatide among older adults has been on the rise since FDA approval was issued, however the effects of tirzepatide use on functional outcomes in older adults with obesity are not well established. Recent studies show that weight loss caused by tirzepatide may be driven by substantial loss of lean muscle mass, which may contribute to weakness and frailty, particularly among older adults. The proposed pilot study aims to evaluate how treatment with tirzepatide for 6 months affects muscle mass and function among older adults, and if changes in muscle mass are linked to changes in functional status over the same time period.

This study is a pilot, single-arm, open-label clinical trial to evaluate the effects of Tirzepatide on muscle mass, strength, and vascular health among older adults with obesity. This study is set in South Texas, where rates of obesity and related health issues, including type 2 diabetes and cardiovascular conditions, exceed national averages and where aging-related diseases are on the rise. Tirzepatide is a new FDA approved medication that promotes weight loss and improves health by targeting specific pathways in the body. While it has been shown to be effective in managing weight and blood sugar levels, there is less information about the kind of weight loss it induces, and how weight loss impacts measures of muscle mass, strength and mobility. This is especially concerning for older adults, as losing muscle mass can lead to weakness, falls, and disability.

Inclusion Criteria

• Men and postmenopausal women aged 50 years or older.
• Body Mass Index (BMI) ≥30 kg/m².
• Untreated HbA1c <6.5% at baseline.
• Willingness and ability to comply with all study procedures, including fasting requirements for certain visits.
• Able to provide informed consent and participate in all study assessments.

Exclusion Criteria

• Active diagnosis of type 2 diabetes mellitus (T2DM), defined by active use of glucose-lowering medications or hemoglobin A1c ≥ 6.5%.
• Body Mass Index (BMI) ≥ 40 kg/m².
• Moderate to severe gastroesophageal reflux disease based on patient history.
• Inability to comply with the treatment protocol or to understand the consent form.
• Chronic Kidney Disease (CKD) Stage 4.
• Aspartate aminotransferase (AST) > 33 U/L or alanine aminotransferase (ALT) > 36 U/L.
• Active pregnancy.
• Personal or family history of medullary thyroid carcinoma.
• Personal or family history of multiple endocrine neoplasia type 2 syndrome.
• Personal history of gastroparesis.
• Personal history of diabetic retinopathy.
• Known serious hypersensitivity, including anaphylaxis and angioedema, to Tirzepatide or any of its excipients.
• Known serious hypersensitivity, including anaphylaxis and angioedema, to any GLP-1 receptor agonist class of therapies.
• Concomitant treatment with GLP-1 receptor agonist therapy

De-identified individual participant data that underlie the results reported will be available in accordance with ICMJE policy.

Data will be available beginning 1 year after the end of the trial and publication of the primary outcomes, and will be available for 24 months.

Data will be available to researchers who provide a methodologically sound proposals. Proposals should be directed to the principal investigators. To gain access, data requestors will need to sign a data access agreement.