Tirzepatide is Eli Lilly's GLP-1/GIP dual agonist, sold as Mounjaro for type-2 diabetes and Zepbound for obesity. The Phase 3 SURMOUNT and SURPASS programs established it as the most potent incretin therapy approved.
SURMOUNT-5, the head-to-head against semaglutide, read out in April 2026 with 21.6% mean weight loss at 72 weeks versus 15.4% for semaglutide; 36.2% of tirzepatide patients hit ≥25% weight loss versus 19.4% on semaglutide. The drug also has FDA approval for moderate-to-severe obstructive sleep apnea via the SURMOUNT-OSA program, and Truveta EHR data presented at OMA 2026 reproduced the head-to-head signal in routine 12-month care.
Like semaglutide, tirzepatide sits on the FDA's April 30, 2026 proposal to exclude branded actives from the 503B bulks list. Stories here track new readouts, the head-to-head economics, and the long compounding fight.
Researchers at Hebrew University and Hadassah Medical Center reported in Diabetes, Obesity and Metabolism on October 7, 2026 a records study of 4,554 matched adults with type 2 diabetes and stage 3 or 4 chronic kidney disease who started a GLP-1 drug or tirzepatide, or finerenone, a non-steroidal kidney drug. Kidney failure or dialysis occurred in 4.8% versus 6.0% within 2.5 years (hazard ratio 0.71), but the absolute risk difference of 1.14 percentage points was not statistically clear. Albuminuria, a key kidney measure, was missing for most people, so the authors warned of residual confounding.
At the Aging Research and Drug Discovery (ARDD) meeting at Harvard on October 1-3, 2026, Novo Nordisk researchers reported that in protein data from 10,052 participants in five semaglutide trials, the drug lowered an estimate of heart biological age by about 2 to 4 years at the first follow-up measurement, according to the meeting's poster abstracts. Longevity.Technology reported on October 4 that Novo also modeled SELECT trial results in a UK cohort of 19,117 people to project 1.9 life-years gained, and that a Lilly epigenetic substudy with 71 paired SURMOUNT-5 participants found all 15 epigenetic clocks showed less aging than the 1.38 years that had passed, two of them statistically significant. Lilly called its work preliminary and hypothesis-generating, with no placebo or control group, and biological-age clocks are not established clinical outcomes.
A retrospective study from two centers in Palermo, Italy, published online September 25, 2026 in the Journal of Diabetes and Its Complications and reported by News-Medical on October 2, followed 122 adults with overweight or obesity and no diabetes who took tirzepatide alongside a standardized low-carbohydrate diet and tailored exercise. After 24 weeks, at a mean final dose of 5.32 mg, average weight fell from 95 kg to 80 kg, fat mass fell 35.4% and fat-free mass 5.1% on bioelectrical impedance, and the authors reported that skeletal muscle was preserved. The study had no control group, used bioimpedance rather than DXA scans, and included only people who completed the 24 weeks.
Lilly announced on Tuesday, September 29, 2026 an indirect treatment comparison, presented at EASD, of Zepbound (tirzepatide) 10 mg and 15 mg against Novo's Wegovy HD (semaglutide 7.2 mg), using its own SURMOUNT-1 trial and Novo's STEP UP trial in adults with obesity and without diabetes. At 72 weeks, under the treatment-regimen estimand, Zepbound 15 mg and 10 mg were estimated to give 4.5 and 3.2 percentage points more weight loss; under the efficacy estimand, the differences were 1.8 and 0.7 points and were not statistically significant. Lilly said discontinuation for adverse events was comparable; the analysis was Lilly-funded, and the two drugs have not been tested head to head at these doses.
A cross-sectional, case-control study presented at the European Academy of Dermatology and Venereology Congress in Vienna (September 30 to October 3, 2026) compared 575 GLP-1 receptor agonist users with 1,329 people with type 2 diabetes, obesity, or both who had never taken the drugs, in France, the U.S., Brazil, and Mexico. Users reported nail detachment far more often (39% vs. 9%), along with nail discoloration (46% vs. 17%) and unusual hair loss (50% vs. 34%); after adjustment, nail detachment and discoloration remained roughly two to three times as frequent. The symptoms were self-reported, about half of users said they had nail problems before treatment, and the design cannot show that the drugs cause these changes; Gizmodo reported that the work was funded by Pierre Fabre.
Two retrospective analyses by Shields Health Solutions and partner health systems, presented at the NASP inSPire2026 specialty pharmacy meeting (September 22-25) and reported by AJMC on September 25, 2026, examined GLP-1 therapy managed by health-system specialty pharmacies. At NYU Langone Health, 115 of 2,943 adults (83.4% commercially insured) who started injectable liraglutide, semaglutide, dulaglutide, or tirzepatide between August 2022 and May 2025 stopped within a year (3.9%), with stopping defined as at least 70 days without medication on hand; rates were 1.8% for tirzepatide, 6.1% for semaglutide, 5.9% for dulaglutide, and 25% for liraglutide. A second analysis of 1,707 patients found a median of five days from prescription to first dispense, prior authorization for 95%, and a median out-of-pocket cost of $24.98; the authors noted the single-organization design and lack of a comparison group.
Lilly announced on Wednesday, September 30, 2026 Phase 2b results for EloraTZP, the amylin receptor agonist eloralintide given with tirzepatide as separate injections, in 367 adults with obesity or overweight and type 2 diabetes across 10 arms. At 48 weeks, under the efficacy estimand, eloralintide 9 mg plus tirzepatide 15 mg produced 23.3% weight loss versus 14.8% with tirzepatide 15 mg alone and 3.0% with placebo, and A1C fell 2.9 points versus 2.4 and 0.3 from a baseline near 8.1%. Discontinuation for adverse events was 10.8% to 27.0% with the combinations, 2.9% with tirzepatide alone, and 16.7% with placebo, and gastrointestinal events were more frequent on the combinations. Lilly plans to start Phase 3 trials of a co-formulated EloraTZP product by the end of 2026 with an adjusted dose-escalation schedule.
Novo announced on Tuesday, September 29, 2026 results of COMPETE SWITCH CV, a retrospective analysis of U.S. claims data from Komodo Health (January 2018 to September 2025) in adults with type 2 diabetes who had been taking semaglutide 1 mg. Over up to 720 days, the 185,705 people who escalated to semaglutide 2 mg had a 6% lower adjusted risk of death, heart attack, or stroke than the 23,104 who switched to tirzepatide (adjusted hazard ratio for switching 1.06; 95% CI 1.04 to 1.08). Novo said the analysis shows an association rather than cause and effect, may carry residual confounding, and did not assess safety outcomes.
The FDA issued a warning letter dated September 18, 2026 to Houston-based Empower Pharmacy after a November 3-14, 2025 inspection, saying its compounded semaglutide and tirzepatide products appear to be 'essentially copies' of FDA-approved drugs and did not meet the conditions of section 503A. The agency said prescriber determinations of a 'significant difference' appeared to be repeated verbatim across many records, suggesting they may be pre-generated, and called the differences between Empower's products and the approved drugs 'pretextual.' The letter also cites insanitary conditions, including inadequate smoke studies of airflow in the ISO 5 area and media fills not run under the most challenging conditions. Empower has 15 working days to respond; BioSpace reported the letter on September 24.
An updated systematic review by Areesha Moiz, Mark Eisenberg, and colleagues, published online September 1, 2026 in the Annals of Internal Medicine, covered 38 randomized trials in 25,816 adults with overweight or obesity and without diabetes, adding 14 trials to the authors' earlier review. Among marketed drugs, the highest placebo-subtracted weight loss reported was 5.8% for liraglutide, 14.8% for subcutaneous semaglutide, 14.3% for oral semaglutide, 12.4% for orforglipron, and 19.0% for tirzepatide; emerging agents reached 23.9% with amycretin and 22.1% with retatrutide. Gastrointestinal adverse events occurred in 76.0% of patients on GLP-1 drugs versus 40.1% on placebo, and discontinuation for adverse events was 10.7% versus 3.4%. The authors said heterogeneity prevented a pooled quantitative analysis, so these figures are the highest values from individual trials rather than combined estimates.
A systematic review and meta-analysis of head-to-head comparisons of tirzepatide (Mounjaro/Zepbound) versus semaglutide (Ozempic/Wegovy) in adults with overweight or obesity — published in Diabetes, Obesity and Metabolism and covered by Medscape on September 9, 2026 with running weekend commentary — synthesized 10 studies (three randomized controlled trials and seven retrospective cohort studies) enrolling 41,381 adults. Tirzepatide produced a mean 4.28 percentage-point greater percent-body-weight reduction than semaglutide (10 studies) and a mean 4.43 kg greater absolute weight loss (8 studies). One head-to-head study reported average weight loss of 50.3 lbs (22.9 kg) on tirzepatide versus 33.1 lbs on semaglutide. Gastrointestinal adverse events were common in both arms but somewhat more frequent with tirzepatide; serious adverse event rates were rare but higher on tirzepatide than semaglutide. The pooled evidence supports the SURMOUNT-5 head-to-head randomized readout published in the New England Journal of Medicine in 2025 (Zepbound 20.2% vs Wegovy 13.7% weight loss at 72 weeks). The tirzepatide-semaglutide efficacy gap plus the safety trade-off remains a live clinical decision point in a market where 12%+ of U.S. adults are on the GLP-1 class per recent surveys.
H1 2026 GLP-1 franchise reporting places Eli Lilly (NYSE: LLY) tirzepatide (Mounjaro plus Zepbound) at nearly $27.7 billion in first-half revenue, an 88% year-over-year increase, versus Novo Nordisk (NYSE: NVO) semaglutide (Ozempic plus Wegovy plus Rybelsus plus Wegovy pill) at approximately $17.5 billion. The revenue gap between the two GLP-1 leaders has widened from under $2 billion at the same point last year to $10.2 billion, driven by Zepbound share gains in U.S. obesity following SURMOUNT-5 superiority data over Wegovy, Mounjaro upside in international markets (China +93% CER, Rest of World +136%), Foundayo (orforglipron) first commercial quarter contribution of $98 million, and semaglutide patent expiries approaching in select markets (generic Ozempic expected in Canada). Novo has cut 12,000 positions in H1 2026 and lowered gross margin outlook to 78%, while Lilly raised full-year 2026 revenue guidance to $85-87 billion.
Novo Nordisk (NYSE: NVO) shares fell approximately 6% Thursday August 13, 2026 on broker downgrade citing continued franchise-gap pressure from Eli Lilly's tirzepatide franchise (Mounjaro + Zepbound) and the CagriSema head-to-head miss against tirzepatide. Specifics: CagriSema (cagrilintide 2.4 mg plus semaglutide 2.4 mg fixed-dose combination) reached 23.0% weight loss at 84 weeks versus tirzepatide 15 mg's 25.5% in the REDEFINE 4 head-to-head Phase 3 trial published in early August 2026. The August 4 H1 2026 earnings release raised full-year 2026 sales guidance to down 3% from a prior down 8% midpoint at constant exchange rates. The broader investor narrative continues to focus on Novo's ability to defend GLP-1 franchise economics against Eli Lilly's Q2 2026 $23 billion revenue blowout (+48% year-over-year), Foundayo (orforglipron) $98 million first commercial quarter, and retatrutide's 28.7% Phase 3 TRIUMPH-4 weight loss result at 68 weeks. Analyst attention now shifts to Novo's Wegovy 7.2 mg higher-dose FDA review, the amycretin oral amylin monotherapy Phase 1b program (roughly 22% weight loss at Week 36), and next-generation candidates in Novo's pipeline. Investors are also watching the CagriSema FDA decision expected late 2026 and whether the label expansion strategy can offset the competitive pressure.
Novo Nordisk released detailed data from the REDEFINE 4 head-to-head 84-week Phase 3 trial of CagriSema (cagrilintide 2.4 mg + semaglutide 2.4 mg fixed-dose combination) versus tirzepatide 15 mg. Trial design: 809 randomized adults with obesity and one or more comorbidities with mean baseline body weight of 114.2 kg, both drugs administered once weekly subcutaneously over 84 weeks. Primary endpoint results: CagriSema 23.0% weight loss versus tirzepatide 25.5% (treatment-policy estimand); CagriSema 20.2% versus tirzepatide 23.6% (treatment-regimen estimand). The trial missed the primary non-inferiority endpoint on weight loss for CagriSema compared to tirzepatide at 84 weeks. CagriSema safety profile was generally well-tolerated. The trial result complicates the Novo commercial positioning of CagriSema as its tirzepatide-beating differentiated response, though the FDA decision on the CagriSema obesity indication remains expected late 2026 based on the REDEFINE 1 and REDEFINE 2 pivotal trials submitted December 18, 2025. The head-to-head result adds to the widening Lilly-Novo franchise gap: Lilly Q2 2026 Mounjaro + Zepbound reached $14.9 billion in the quarter, while Novo H1 2026 sales reached 78.49 billion Danish kroner ($12.09 billion).
The higher-dose Wegovy 7.2 mg (semaglutide 7.2 mg once weekly subcutaneous injection, up from the current 2.4 mg maximum approved dose) is currently under FDA review for the adult obesity indication. The submission is based on the Phase 3 STEP UP trial that documented approximately 19% weight loss at the 7.2 mg dose over 68 weeks, versus approximately 15% weight loss for the currently-approved 2.4 mg dose (based on STEP 1 registrational data). The higher-dose submission provides Novo Nordisk with a line-extension option to defend the Wegovy franchise economics against the Eli Lilly tirzepatide franchise (Zepbound and Mounjaro), which continues to outperform on weight loss (approximately 21% at the 15 mg weekly dose per SURMOUNT-1). The Wegovy 7.2 mg efficacy also lags the Lilly retatrutide triple-agonist Phase 3 TRIUMPH-4 data that documented 28.7% mean body weight reduction at the 12 mg dose (the highest weight-loss magnitude in any Phase 3 obesity trial to date). Novo Nordisk's line-extension strategy is under scrutiny following the CagriSema REDEFINE 4 head-to-head miss versus tirzepatide (23.0% vs 25.5% treatment-policy estimand at 84 weeks). FDA decision timing on Wegovy 7.2 mg has not been publicly disclosed.
Novo Nordisk's experimental CagriSema (cagrilintide plus semaglutide fixed-dose combination) reportedly failed to control blood sugar as effectively as Eli Lilly's tirzepatide (Mounjaro/Zepbound) in a head-to-head Phase 3 trial of patients with type 2 diabetes. CagriSema regulatory filing was submitted December 18, 2025 with an expected FDA decision in late 2026 for obesity indication; the type 2 diabetes head-to-head failure complicates the commercial narrative and label-expansion strategy. The trial outcome adds to the widening Lilly-Novo franchise gap documented across the Q2 2026 earnings week: Eli Lilly (NYSE: LLY) Q2 revenue reached $23 billion (+48% year-over-year) with Foundayo (orforglipron oral small-molecule GLP-1) delivering $98 million in its first fully operational commercial quarter and Mounjaro + Zepbound combined at $14.9 billion; Novo Nordisk H1 2026 sales reached 78.49 billion Danish kroner ($12.09 billion, +3% constant currency) with shares declining 5% on margin-compression concerns despite raised guidance. Investor narrative on Novo's ability to defend GLP-1 franchise economics continues to deteriorate as the amylin analog (cagrilintide) that Novo positioned as its differentiator against tirzepatide's dual GIP/GLP-1 mechanism failed to close the efficacy gap in the head-to-head setting.
Eli Lilly (NYSE: LLY) reported Q2 2026 earnings Wednesday August 5, 2026 with revenue of $23 billion (+48% year-over-year), well ahead of analyst consensus of $20.5 billion. Full-year 2026 revenue guidance was raised to $85-87 billion from the prior $82-85 billion range. Mounjaro (tirzepatide for type 2 diabetes) revenue rose 91% to $9.9 billion, split $4.8 billion US and $5.2 billion international, with the international majority driven by aggregate international Mounjaro market share now above 50% per prior Lilly executive commentary. Zepbound (tirzepatide for obesity) delivered $4.9 billion in US revenue (+44% year-over-year), with strong prescription-volume growth more than offsetting the low-to-mid-teens price erosion Lilly had guided to for FY26. Foundayo (orforglipron, the first oral small-molecule GLP-1 receptor agonist approved by FDA in April 2026) generated $98 million in its first fully operational commercial quarter, providing the first commercial-earnings-line view of the oral small-molecule GLP-1 category. Combined Mounjaro + Zepbound franchise revenue reached $14.9 billion, representing approximately 65% of total Lilly revenue for the quarter. LLY shares rose approximately 4% intraday on the earnings and guidance beat. Analyst commentary flagged the substantial widening of the Lilly-Novo obesity franchise gap.
A CROI 2026 (Conference on Retroviruses and Opportunistic Infections) analysis presented earlier in 2026 documented that GLP-1 weight-loss medications generally work well for people living with HIV who are stable on antiretroviral therapy. Beyond the known obesity and type 2 diabetes benefits, the CROI analysis reported potential improvements in liver, gut, and cardiovascular health, plus reduced smoking rates in the HIV population on GLP-1 therapy. Real-world analysis of people living with HIV prescribed semaglutide (Wegovy, Ozempic) or tirzepatide (Mounjaro, Zepbound) documented comparable weight loss to general-population Phase 3 trial data with no new safety signals specific to the HIV population. Approximately 40% of people living with HIV in the US also have obesity, and cardiovascular disease is one of the primary drivers of morbidity and mortality in the HIV-treated population. The CROI analysis supports GLP-1 therapy as a reasonable consideration in HIV patients with obesity or metabolic-syndrome comorbidities, particularly following the AIDS 2026 conference programming that concluded Friday July 31 in Rio de Janeiro emphasizing the sustained management of HIV alongside comorbid conditions in the current global funding-constrained environment. The finding also intersects with the ongoing peptide-adjacent HIV therapeutic landscape covered by the July 2026 Gilead-Merck ISLEND-1 and ISLEND-2 once-weekly islatravir/lenacapavir data and the Merck alimatravir monthly HIV prevention pill.