Quick answer: there is no approved retatrutide maintenance dose, because the drug is not yet FDA-approved. In the phase 3 TRIUMPH trials, the maintenance doses were 4 mg, 9 mg or 12 mg once weekly, reached after a dose-increase period of up to 16 weeks and then held for about 64 weeks.[1][2] What happens when people stop retatrutide has not been published; the trial that will show it, TRIUMPH-6, is expected to finish in 2028.[7]
Retatrutide is an investigational Eli Lilly drug. The doses below are research doses, not a prescription, and a clinician would set any dose once a label exists. For the full background, see the retatrutide profile.
What “maintenance dose” means in the trials
Retatrutide trials split treatment into two phases:
- Dose escalation. Everyone started at 2 mg once weekly and stepped up every four weeks.[2]
- Maintenance. Once people reached their assigned dose, they stayed on it. The trial design paper describes the 80-week trials as 16 weeks of escalation followed by 64 weeks of maintenance.[1]
So in trial language, the maintenance dose is simply the target dose a person was randomly assigned to. It is not a lower dose for keeping weight off, which is how the phrase is sometimes used online.
| Maintenance dose | Steps to get there | Reached at | Tested in |
|---|---|---|---|
| 4 mg | 2, 4 mg | Week 4 | TRIUMPH-1, TRIUMPH-2 |
| 9 mg | 2, 4, 6, 9 mg | Week 12 | TRIUMPH-1 to TRIUMPH-4 |
| 12 mg | 2, 4, 6, 9, 12 mg | Week 16 | TRIUMPH-1 to TRIUMPH-4 |
Sources: TRIUMPH design paper[1] and Lilly’s TRIUMPH-2 and TRIUMPH-3 report.[2] See the retatrutide dosage guide for earlier trials, which used maintenance doses from 0.5 mg to 12 mg.[5][6]
The phase 2 diabetes trial also tested whether the route to a maintenance dose matters. Reaching 8 mg from a 2 mg start or a 4 mg start gave similar results at 24 weeks: HbA1c fell 1.99 versus 1.88 percentage points.[6] In the obesity trial, the lower 2 mg start partly reduced stomach side effects.[5]
How each maintenance dose performed
In TRIUMPH-1, average weight change at 80 weeks, counting everyone randomized, was:[3]
- 4 mg: −17.6%
- 9 mg: −23.7%
- 12 mg: −25.0%
- Placebo: −3.9%
The jump from 4 mg to 9 mg was large, but 9 mg to 12 mg added only about 1.3 percentage points. Side effects pointed the other way: 4.1% of people on 4 mg stopped because of adverse events, versus 11.3% on 12 mg and 4.9% on placebo.[4] Lilly has highlighted that 4 mg needs only a single dose step.[4]
The phase 2 obesity trial showed the same flattening: weight loss at 48 weeks was 22.8% on 8 mg and 24.2% on 12 mg.[5] For the full results, see retatrutide weight loss results.
When doses were lowered
The TRIUMPH protocols allowed a permanent dose reduction in three situations:[1]
- stomach side effects or poor food intake that did not improve with other measures, including a previous attempt to step down and back up
- a BMI that fell to 22 or below
- a participant feeling they had lost too much weight
That last point matters. In TRIUMPH-4, Lilly said discontinuation rates were closely linked to starting weight and included people who stopped because they perceived excessive weight loss.[12]
Staying on longer: the 104-week extension
TRIUMPH-1 included a pre-specified extension to 104 weeks. It enrolled 532 people who started with a BMI of 35 or more, finished 80 weeks and tolerated their dose. In the extension they received the highest dose they could tolerate, 9 or 12 mg. Those originally assigned to 12 mg reached an average loss of 30.3% at 104 weeks.[4]
That shows weight can keep falling on continued treatment in a selected group. It does not show what dose is needed to hold a weight steady once loss has stopped, and there are no published data beyond about two years.
What happens if you stop retatrutide
No retatrutide trial has yet published what happens after people stop. The phase 3 trials included only a short follow-up after treatment; TRIUMPH-2’s was four weeks.[2]
TRIUMPH-6 is designed to answer the question. All 643 participants take retatrutide for 80 weeks. They are then randomized for 36 weeks to stay on their dose, switch to a second dose, or switch to placebo. The main result is weight change at week 116, with primary completion estimated for April 2028.[7]
Until then, the best guide is what happened with related drugs:
| Trial | Drug | What happened after switching to placebo |
|---|---|---|
| STEP 1 extension | Semaglutide 2.4 mg | Regained about two-thirds of lost weight within a year of stopping |
| STEP 4 | Semaglutide 2.4 mg | Weight rose 6.9% over 48 weeks, vs a further 7.9% loss on drug |
| SURMOUNT-4 | Tirzepatide 10 or 15 mg | Weight rose 14.0% over 52 weeks, vs a further 5.5% loss on drug |
Sources: STEP 1 extension,[9] STEP 4[10] and SURMOUNT-4.[11]
In SURMOUNT-4, 89.5% of people who stayed on tirzepatide kept at least 80% of their earlier weight loss, versus 16.6% of those switched to placebo.[11] In the STEP 1 extension, improvements in heart and metabolic risk factors also drifted back toward where they started.[9] The STEP 1 authors concluded that ongoing treatment appears to be needed to maintain the improvements, and the SURMOUNT-4 authors found that stopping tirzepatide led to substantial weight regain.[9][11]
Retatrutide may behave the same way, but that is an assumption until TRIUMPH-6 reports. For practical guidance on this drug class, see stopping GLP-1 medications and keeping weight off after a GLP-1.
Other open questions
- Different escalation schedules. TRIUMPH-9 is comparing three dose-escalation schemes over 104 weeks in 600 adults, with results expected around October 2028.[8]
- Comparisons with approved drugs. The tirzepatide and semaglutide labels already define maintenance doses; see tirzepatide maintenance dose and semaglutide maintenance dose.
Questions to ask a clinician
- Once I reach my goal on an approved medicine, should we keep the same dose or lower it?
- What is our plan if side effects make the current dose hard to stay on?
- What should I expect if I stop, and how would we manage regain?
- Would I qualify for a retatrutide trial, such as one studying maintenance?
