Pooled analysis finds tirzepatide works about the same in adults 65 and older

A pooled analysis combining seven Phase 3 trials of tirzepatide (Zepbound/Mounjaro) found that weight loss, cardiometabolic improvements and quality-of-life gains in adults aged 65 and older were broadly similar to those seen in younger adults, according to research published June 16, 2026, in Diabetes, Obesity and Metabolism ^[1].

The analysis combined data from SURMOUNT-1 through SURMOUNT-5, including the 3-year SURMOUNT-1 extension, plus SURMOUNT-OSA and SUMMIT ^[1]. Together these trials tested tirzepatide across different groups: adults with obesity alone, obesity with type 2 diabetes (SURMOUNT-2), obesity with heart failure with preserved ejection fraction, or HFpEF (SUMMIT), and obesity with obstructive sleep apnea (SURMOUNT-OSA) ^[1]. Researchers compared outcomes in participants aged 65 and older against those under 65 ^[1].

Across the pooled trials, tirzepatide produced clinically meaningful weight reduction along with favorable changes in cardiometabolic risk factors and quality-of-life measures in the older group, with results described as broadly comparable to younger participants ^[1]. In SUMMIT, tirzepatide was linked to a lower risk of a combined outcome of cardiovascular death or worsening heart failure in people with HFpEF and obesity ^[1]. In SURMOUNT-OSA, the drug produced clinically meaningful changes in sleep-disordered breathing ^[1]. In the 3-year SURMOUNT-1 data, people with obesity and prediabetes who took tirzepatide had sustained weight loss and a lower risk of progressing to type 2 diabetes ^[1].

On safety, the researchers reported no clinically meaningful differences between tirzepatide and placebo in older adults for gastrointestinal tolerability, falls, fractures, depression-related outcomes, pancreatitis, or kidney, liver, gallbladder and biliary-related adverse events ^[1]. The paper's authors concluded that no clinically relevant risks beyond those already inherent to older age were detected when comparing the two age groups ^[1]. The study was a post hoc analysis, meaning it looked back at data collected for other purposes rather than being designed from the start to test outcomes in older adults specifically ^[1]. The paper does not report the precise numerical weight-loss or symptom differences between age groups, only that they were broadly comparable ^[1].

The study's authors include researchers from King Fahad Medical City, Northwestern University's Feinberg School of Medicine, and Eli Lilly and Company, which manufactures tirzepatide ^[1]. The paper notes that in the United States, about 30% of adults 65 and older have obesity, a share expected to keep rising as the population ages ^[1]. By 2050, roughly one in three adults over 25 is projected to have obesity, with a quarter of that group over age 65 ^[1].

Why it matters for patients

Older adults with obesity face particular concerns that don't apply as strongly to younger patients, including risk of muscle loss, or sarcopenia, and functional decline that can worsen frailty during weight loss ^[1]. The authors note that lifestyle changes alone can be harder to sustain for people with severe obesity or physical limitations, and that bariatric surgery tends to be less effective and riskier in older patients compared with younger ones ^[1]. Against that backdrop, this analysis suggests tirzepatide's benefits and risk profile do not meaningfully differ by age, which the authors say supports its use in older adults when weighing risks and benefits ^[1]. The findings do not address every possible concern for older patients, such as long-term muscle mass changes, since the paper describes broad comparability rather than detailed subgroup numbers ^[1].

What happens next

The analysis was published June 16, 2026, in Diabetes, Obesity and Metabolism ^[1]. It does not specify further planned studies focused specifically on older adults, and additional detail on exact outcome differences by age group is not included in the published abstract ^[1].