Eli Lilly’s experimental triple‐agonist GLP-1 candidate retatrutide delivered an average body-weight reduction of 28.7% at 68 weeks in its pivotal phase 3 SURMOUNT-2 study. This result outstrips the 26.6% weight loss observed for tirzepatide in a separate trial, despite the latter including 12 weeks of intensive lifestyle counseling. The trial enrolled over 1,200 adults with obesity (BMI ≥30 kg/m2) or overweight (BMI ≥27 kg/m2) with comorbidities, and evaluated three dosage arms; the 12 mg cohort achieved the most pronounced weight loss, with two other doses also showing statistically significant outcomes versus placebo.

In a prespecified exploratory analysis, more than 12% of retatrutide-treated participants with concurrent knee osteoarthritis reported complete resolution of knee pain by week 68, compared to under 4% in the placebo group. This finding was measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. Lilly cites this as the first indication that GLP-1-based therapies could exert anti-nociceptive effects, potentially opening pathways for FDA submissions in osteoarthritis and other chronic pain conditions.

In the quarter ending September 30, 2025, Lilly’s GLP-1 products Mounjaro and Zepbound generated combined revenues of $10.1 billion, underpinning a 54% year-over-year increase in total quarterly sales to $17.6 billion. These injectables now account for more than half of the company’s top-line growth, reinforcing Lilly’s leadership in metabolic therapies. Management forecasts that the addition of retatrutide, pending regulatory approval, could boost GLP-1 revenues by an incremental $3–4 billion annually within two years of launch.

With an FDA action date for an oral GLP-1 candidate slated for late 2026 and the planned initiation of a dedicated pain indication trial in mid-2026, Eli Lilly expects multiple catalysts over the next 12 months. The company has allocated $1.2 billion in R&D funding for its metabolic franchise this fiscal year, prioritizing head-to-head studies against competitive products and long-term safety assessments. Analysts project that the broader therapeutic applications of retatrutide could extend its peak annual sales potential to over $6 billion, reinforcing Lilly’s growth trajectory through the end of the decade.