Retatrutide Statistics: The Key Numbers in One Place (2026)

Retatrutide statistics, as of October 31, 2026: six Phase 3 trials have reported, 7,720 people were randomized across them (our sum of Lilly's per-trial figures), and the top dose cut body weight by 16.8% to 28.7% on average depending on the trial (efficacy estimand). Every number below comes from a Lilly release, a journal paper or the ClinicalTrials.gov registry, and each table names its source. Last checked October 31, 2026.

Retatrutide is still investigational, so these are trial numbers, not label numbers. Where Lilly published two versions of a result, the tables say which one you're reading. For the story behind each trial, follow the links to the Phase 3 results page.

Retatrutide trials and how many people were enrolled

Lilly states no combined total for the six reported trials. Its own per-trial randomized counts (TRIUMPH-4 and TRIUMPH-1 releases, the TRANSCEND-T2D releases and the October 2026 Lilly FAQ) add up to 7,720.

Lilly's program-level counts are bigger because they include trials that haven't reported: more than 5,800 participants in the 4 TRIUMPH registrational trials and more than 2,050 in the 3 TRANSCEND-T2D trials. The earlier Phase 2 obesity trial enrolled 338 adults (NEJM 2023).

Retatrutide statistics on weight loss by trial and dose

Lilly's releases lead with the efficacy estimand, which asks what happens if everyone stays on the drug. The treatment-regimen estimand counts everyone randomized, and it's lower. Both are below, as average percent of body weight lost.

Efficacy estimand, from Lilly's releases. The treatment-regimen versions, where Lilly or the journal published them:

In the Phase 2 trial, 12 mg produced a 24.2% loss at 48 weeks against 2.1% on placebo (NEJM 2023). TRIUMPH-1's 104-week extension, which enrolled 532 people with a starting BMI of 35 or higher, reached 30.3% on 12 mg (efficacy estimand, escalating to a maximum tolerated dose). More on dose differences at retatrutide weight loss results.

A1C statistics

A1C is the three-month blood sugar average, in percent. Entries are points of A1C lost from the starting value, on the efficacy estimand.

In TRIUMPH-2, 73.1%, 79.2% and 79.0% of people on 4, 9 and 12 mg reached an A1C of 6.5% or below, against 26.3% on placebo. The head-to-head with Ozempic is the only reported trial that tests a rival drug on A1C:

TRANSCEND-T2D-2 was open-label and Lilly has released only the efficacy estimand, with no paper yet. Detail on the TRANSCEND-T2D-2 trial page.

Liver fat statistics

The only liver fat data are from a 98-person substudy of the Phase 2 trial, in people with at least 10% liver fat on MRI (Nature Medicine 2024). Relative liver fat fell 81.4% on 8 mg and 82.4% on 12 mg at 24 weeks, against a 0.3% rise on placebo, and 86% of people on 12 mg got to normal liver fat (under 5%).

Two caveats come with the numbers. MRI data existed for 78.6% of the substudy at week 24 but only 43.9% at week 48, and no Phase 3 liver result has been published.

Side effects and stopping rates

Nausea and diarrhea lead the lists in every trial. This table shows the 12 mg arm, the top dose, and the share who stopped treatment because of side effects.

Dysesthesia means burning or oversensitive skin. Rates in the placebo arms were lower in every case: in TRIUMPH-1, nausea was 14.8% and dysesthesia 0.9% on placebo. The TRIUMPH-1 abstract gives no serious adverse event rate, and we haven't listed any here. For what these feel like, see is retatrutide safe.

Sleep apnea and knee pain numbers

Both come from baskets nested in the big obesity trials, so they have fewer people. The sleep apnea table gives the average drop in apnea-hypopnea index (AHI, breathing pauses per hour) on the hybrid-treatment estimand (NEJM, Oct 21, 2026).

Knee pain is measured on the WOMAC pain scale, where 0 is no pain and 10 is worst. Points lost from a starting 6.0:

The TRIUMPH-1 basket also had a 4 mg arm, which lost 3.2 points. In TRIUMPH-4, 14.1% on 9 mg and 12.0% on 12 mg were completely free of knee pain at 68 weeks (post hoc), against 4.2% on placebo.

Half-life and dosing facts

Everyone in TRIUMPH starts at 2 mg. The target dose is 4, 9 or 12 mg in TRIUMPH-1 and -2, and 9 or 12 mg in TRIUMPH-3 and -4. Details are on the half-life page.

Regulatory timeline

Lilly last said, on September 29, 2026, that it plans to submit retatrutide to the FDA in the first quarter of 2027 as a Biologics License Application (BLA). On October 2, 2026, the FDA decided that retatrutide is a drug, not a biological product, so an application would need to be filed under section 505 of the Federal Food, Drug, and Cosmetic Act. Lilly's appeal on that question is pending in the Seventh Circuit, and we found no ruling as of October 31, 2026. No approved version exists yet, and anything sold online as retatrutide for sale is not Lilly's product. Lilly has announced no price.

ClinicalTrials.gov counts

We pulled the registry on October 31, 2026.

Still pending, with the registry's estimated dates: TRIUMPH-5 against tirzepatide (about 800 people, primary completion November 2026) and TRANSCEND-T2D-3 in kidney impairment (about 320 people, primary completion October 2026). The full list sits on the trial tracker.

Our read: the weight numbers are large in every population tested, but they all come from Lilly's own trials, and journal papers cover only 3 of the 6 reported ones. A stat that doesn't name its estimand could be off by 3 points or more, as the two TRIUMPH-1 figures (28.3% and 25.0%) show.