Retatrutide: 9 mg delivers 93% of the 12 mg weight loss with fewer dropouts

Lilly says retatrutide cut weight 20.9% against 9.4% on Ozempic at 80 weeks. The lower dose gets within 1.4 points of that, so the commercial question is the dose, not the beat.

Eli Lilly's lower retatrutide dose gives 93% of the weight loss of the higher dose with 39% fewer side effect dropouts. The 9 mg arm lost 19.5% of body weight against 20.9% on 12 mg. Dropouts for side effects were 4.8% against 7.9%. That dose gap will determine the label and profit margin beyond the win over Ozempic.

Lilly says retatrutide cut body weight by 20.9% in adults with type 2 diabetes, where Novo Nordisk's Ozempic managed 9.4% over the same 80 weeks. Lilly shares were up about 1.2% at $1,297.67 in Wednesday trading, a delayed quote, a day before third quarter results.

Beating Ozempic is the easier comparison. Lilly's topline release from the TRANSCEND-T2D-2 trial lets us measure the step from 9 mg to 12 mg. Lilly's own tirzepatide, sold as Mounjaro, is the rival that will set the price.

What the two doses delivered

The trial randomised 1,298 adults with type 2 diabetes on metformin, with or without an SGLT2 inhibitor. They were split 2:2:1 between retatrutide 9 mg, retatrutide 12 mg and Ozempic 2 mg. Patients started at 2 mg and moved up every four weeks to their target dose.

The lower dose delivers 93% of the higher dose's result. Average weight loss was 19.5% on 9 mg and 20.9% on 12 mg. The gap is 1.4 percentage points. On a baseline of 102.4 kg, that is 20.1 kg lost on 9 mg and 21.5 kg on 12 mg.

The extra dose adds dropouts as well as weight loss. Treatment stops for side effects were 4.8% on 9 mg and 7.9% on 12 mg, so 9 mg lost 39% fewer patients. That is 3.1 points. Vomiting ran at 10.2% on 9 mg and 15.0% on 12 mg, against 13.2% on Ozempic. The 9 mg arm is the only retatrutide dose gentler than Ozempic on vomiting.

Blood sugar and side effects

The higher dose adds weight loss without improving glucose control. A1C, the standard blood sugar measure, fell 2.2 points on both doses from a baseline of 8.3%. Ozempic managed 1.8.

Both doses met the A1C test against Ozempic. The primary objective was A1C noninferiority of 12 mg to Ozempic 2 mg. The 9 mg arm posted the same 2.2 point fall and met noninferiority as a key secondary endpoint.

Other side effects also rise with the dose. Dysesthesia, an abnormal skin sensation, ran at 4.8% on 9 mg and 6.5% on 12 mg, against 2.7% on Ozempic. Diarrhea hit 28.3% on 9 mg and 32.7% on 12 mg. Nausea ran at 21.2% and 23.8%, against 21.3% on Ozempic. Constipation was lower on retatrutide, at 14.2% and 13.1% against 19.8%. Lilly calls most events mild to moderate and says they typically resolved during treatment.

Dropouts cost money because chronic drugs earn revenue per month on therapy. On 12 mg, 7.9% of patients stopped for side effects, nearly three times Ozempic's 2.7%. On 9 mg, 4.8% did, 1.8 times. Lilly must price both doses the same or put a premium on 12 mg, and the extra stops eat into that premium. A health plan tiering a weekly injection faces the same choice.

How to read the trial results

All weight figures are Lilly's efficacy estimand, which counts every patient as if they stayed on drug for 80 weeks. On that basis retatrutide's 20.9% is 2.2 times Ozempic's 9.4%. The stop rates above are real discontinuations from the same release. ### The next comparison is tirzepatide

Ozempic 2 mg is the highest approved dose, so the comparison uses Novo's strongest dose.

Diabetes blunts weight loss. In May, obesity patients on 12 mg lost 28.3% over 80 weeks in TRIUMPH-1. Here the same dose delivers 20.9%, 7.4 points less. Lilly's TRIUMPH-2 trial in patients with both diabetes and obesity averaged 20.8% on the highest dose.

Buyers treating obesity may place more value on weight loss. But in obesity, 12 mg already reached 28.3% in TRIUMPH-1, and Reuters reported that about 11% of top dose patients stopped for side effects. In diabetes, the extra point buys nothing on A1C and costs 3.1 points of retention.

Ozempic 2 mg is the right bar for a diabetes label, but payers will price against tirzepatide. TRIUMPH-5 is a double blind Phase 3 trial of 800 adults with obesity, with or without type 2 diabetes. It sets retatrutide directly against tirzepatide, the active ingredient in Lilly's own Mounjaro. The primary endpoint is percent weight change at week 80.

In diabetes, then, retatrutide competes with Lilly first. A drug that must beat a sibling product by enough to justify a higher price has less room than one measured against Novo Nordisk. A point or two of extra weight loss is a thin case for a premium. It arrives with more vomiting, more dysesthesia and more dropouts.

The efficacy story is still strong. Lilly calls this the sixth Phase 3 trial in which retatrutide has delivered powerful efficacy, and the first against another incretin medicine. Citi analyst Geoffrey Meacham said the data strengthen retatrutide's position as a key long term cardiometabolic growth driver. Retatrutide is not approved by FDA or any regulator. Lilly will present detailed results at a medical meeting and publish them in a peer reviewed journal. Reuters reports that Lilly plans to seek US approval next year.

For Novo Nordisk, the 9 mg arm is the uncomfortable result. A dose with 4.8% side effect dropouts lost 19.5% of body weight where Ozempic 2 mg lost 9.4%. That is 10.6 kg more per patient on average. Lilly now offers a dose that doubles Novo's weight loss and loses fewer patients than the 12 mg dose.

The next trial and filing updates

Management can say which dose it will carry into the US filing when it reports on 29 October at 10 a.m. Eastern. The registry record shows an extension that keeps about 650 participants on retatrutide for 24 more weeks, with study completion set for February 2027.

TRIUMPH-5 has a registered primary completion in November 2026 and study completion in December 2026. The 29 October call comes first, and it is the first chance to hear Lilly's dose plan from management.