The European Association for the Study of Diabetes opens its 62nd Annual Meeting in Milan today, and Eli Lilly has flagged a dedicated retatrutide symposium for Wednesday 30 September, 8:30–9:30am CEST, where the full Phase 3 TRIUMPH-2 results will be presented. Until that session, everything the public knows about retatrutide dosing in people with type 2 diabetes comes from a topline press release issued on 23 July 2026 — and buried in it is the most interesting pattern in the whole TRIUMPH programme so far: as the dose went up, weight loss kept climbing, and HbA1c essentially stopped.

What's actually on the EASD agenda

Lilly's 15 September announcement lists three separate symposia in Milan. The retatrutide session on Wednesday morning covers Phase 3 data for the investigational once-weekly GIP, GLP-1 and glucagon triple receptor agonist. Later the same day, at 4:30pm CEST, the company presents Phase 2 results for eloraTZP — a combination of the selective amylin receptor agonist eloralintide with tirzepatide — in adults with obesity or overweight and type 2 diabetes. On Thursday 1 October, Phase 3 results for Foundayo (orforglipron) across the ACHIEVE type 2 diabetes programme get their own slot.

That's three distinct mechanisms from one company inside 48 hours, all aimed at broadly the same patient. Worth keeping in mind when reading any single readout: retatrutide is not competing only with semaglutide and tirzepatide. More on how the molecule itself works is on our what is retatrutide page.

Retatrutide dosing: the weight curve and the A1c curve part ways

TRIUMPH-2 randomised 1,152 adults with overweight or obesity plus type 2 diabetes to once-weekly retatrutide 4mg, 9mg or 12mg, or placebo, for 80 weeks. Mean baseline HbA1c was 7.7%.

The numbers as reported

Mean body weight change at 80 weeks:

  • 4mg: −12.7%
  • 9mg: −19.1%
  • 12mg: −20.8%
  • Placebo: −4%

Mean HbA1c change at 80 weeks:

  • 4mg: −1.4 percentage points
  • 9mg: −1.6 percentage points
  • 12mg: −1.5 percentage points
  • Placebo: −0.2 percentage points

Tripling the dose from 4mg to 12mg bought roughly eight extra percentage points of weight loss. It bought nothing measurable on HbA1c — the 12mg figure is numerically below the 9mg figure. Nobody should read that as 12mg being worse for glucose; these are arm-level averages from a trial powered for weight and A1c versus placebo, not a powered head-to-head between doses, and a 0.1-point difference sits comfortably inside statistical noise. The honest reading is flatter: on glycaemia, the dose–response looks like a plateau, not a slope.

There is a mundane arithmetic reason that plateau is unsurprising, and we'd flag it as interpretation rather than a finding of the trial: HbA1c has a floor. A cohort starting at 7.7% has roughly 1.5–2 points of room before it bumps into the non-diabetic range, whereas body weight has no equivalent ceiling on how much more it can fall. Whatever the cause, the practical implication for prescribers — if and when retatrutide is approved anywhere — is that dose escalation and glycaemic targets may not be the same conversation.

The cross-trial gap: 28.3% versus 20.8%

TRIUMPH-1, in 2,339 adults with obesity or overweight plus a weight-related condition and without type 2 diabetes, reported 28.3% mean weight loss at 12mg over 80 weeks, with 45.3% of that arm losing at least 30%. TRIUMPH-2's 12mg arm landed at 20.8%.

That ~7.5-point gap is consistent with what has been seen across the incretin class, where people with type 2 diabetes generally lose less weight than people without it at the same dose. But it is a comparison between two trials with different populations, different background medications and different entry criteria — not a randomised comparison, and not something either trial was designed to measure. TRIUMPH-3, in 1,949 adults with BMI ≥35 and established cardiovascular disease, sits in between at 21.6% (9mg) and 22.6% (12mg) versus −3.2% on placebo, alongside reported reductions of 37.0% in triglycerides, 16.5% in non-HDL cholesterol, 9.3mmHg in systolic blood pressure, 19.0cm in waist circumference and 51.2% in high-sensitivity CRP. Our clinical trials page tracks the programme arm by arm.

Tolerability at the top of the dose range

TRIUMPH-2 reported discontinuation due to adverse events ranging from 3.8% to 11.6% across the three retatrutide doses, versus 4.9% for placebo. In TRIUMPH-1 the same pattern appeared: 4.1% at 4mg, 6.9% at 9mg, 11.3% at 12mg, against 4.9% on placebo, with dose-related nausea and diarrhoea the most common adverse events.

Put that beside the dosing pattern above and the trade-off gets sharper. Going from 9mg to 12mg roughly doubled the dropout rate in TRIUMPH-1 and added under two points of weight loss in TRIUMPH-2 — with no gain in HbA1c. That is exactly the kind of question a full conference presentation, and eventually a peer-reviewed paper, needs to answer with per-dose detail rather than headline averages. What's known so far about the tolerability profile is collected on our safety page.

Status check: still investigational everywhere

Lilly has said it plans to file for US approval in the first quarter of 2027. Retatrutide has no marketing authorisation in the United States, European Union, United Kingdom or Australia, and it is not TGA-approved — Australians cannot obtain it on prescription, and the Australia page explains where things currently stand locally. Everything above comes from company press releases and a conference agenda; none of the Phase 3 TRIUMPH data has yet appeared as a peer-reviewed publication.

If you want the TRIUMPH-2 presentation covered when it lands on Wednesday, join the free updates list and we'll send it through.

FAQ

What doses of retatrutide were used in the phase 3 trials?

The TRIUMPH Phase 3 trials tested once-weekly subcutaneous retatrutide at 4mg, 9mg and 12mg against placebo over 80 weeks. Titration schedules and any approved dosing would ultimately be set by regulators, and retatrutide is not approved anywhere yet.

Does a higher retatrutide dose lower HbA1c more?

In TRIUMPH-2 it did not appear to. Reported HbA1c reductions were 1.4, 1.6 and 1.5 percentage points at 4mg, 9mg and 12mg respectively, versus 0.2 with placebo — a plateau rather than a dose-dependent slope, while weight loss continued to increase with dose.

Why did retatrutide produce less weight loss in people with type 2 diabetes?

TRIUMPH-2 (type 2 diabetes) reported up to 20.8% mean weight loss versus up to 28.3% in TRIUMPH-1 (no diabetes). Lower weight loss in people with type 2 diabetes is a long-standing pattern across incretin drugs, but this is a comparison between two separate trials rather than a randomised head-to-head, so the size of the gap should be treated cautiously.

When is retatrutide expected to be approved?

Lilly has said it plans to submit retatrutide for US approval in the first quarter of 2027. No regulator — FDA, EMA, MHRA or TGA — has approved it, and no approval date has been announced by any agency.

Sources

Disclaimer: This article is general information only and is not medical advice. Retatrutide is an investigational drug and is not approved by the TGA, FDA, EMA or MHRA; it is not available on prescription in Australia. Always speak with a qualified health professional about weight management or diabetes treatment. retatrutide.net.au is an independent Australian information site and is not affiliated with, endorsed by or sponsored by Eli Lilly and Company.