Mounjaro Maintenance Dose: What SURMOUNT-MAINTAIN Found

Mounjaro can produce substantial weight loss. The harder question comes later: once weight is stable, must the highest tolerated dose continue, can the dose come down, or is it time to stop?

Until recently, the strongest trials mainly compared continued treatment with stopping. SURMOUNT-MAINTAIN added a clinically useful middle option. It tested whether people could reduce tirzepatide to 5 mg after an initial weight-loss phase.

For people who have reached a stable weight on tirzepatide, the trial provides evidence for a middle option that had not previously been tested in a large randomised maintenance trial.

What the trial actually tested

SURMOUNT-MAINTAIN was a phase 3b, double-blind randomised controlled trial published in The Lancet in 2026 by Horn DB and colleagues. Eli Lilly funded the study.

The trial enrolled 441 adults with obesity, or overweight plus at least one weight-related health condition, at 20 sites in the United States. People with type 1 or type 2 diabetes were excluded. Everyone first entered a 60-week open-label weight-loss phase using once-weekly tirzepatide at their maximum tolerated dose of 10 mg or 15 mg.

At week 60, 378 participants were randomly assigned in a 3:3:2 ratio to one of three groups for a further 52 weeks:

• continue the maximum tolerated dose of 10 mg or 15 mg: 140 participants
• reduce to tirzepatide 5 mg: 144 participants
• switch to placebo: 94 participants

A total of 345 participants, 91%, completed the 112-week study. From week 84 onward, 24 weeks after randomisation, rescue tirzepatide could be offered if a participant regained more than half of the weight they had lost.

What happened after 112 weeks

Measured from the original baseline to week 112, estimated average body-weight change was:

These figures come from the trial's primary modified treatment-regimen analysis. It included all randomised participants and assumed that people who started rescue tirzepatide would gain no further benefit from their assigned treatment.

The comparison needs careful reading. All three groups had already completed 60 weeks of active tirzepatide before randomisation. The placebo group therefore remained below its original starting weight on average, but gave back substantially more of the earlier reduction during the maintenance year.

Rescue treatment provides another useful view. Among participants with available observed data, rescue tirzepatide was used by 11 of 138 people (8%) in the maximum-dose group, 35 of 142 (25%) in the 5 mg group and 60 of 90 (67%) in the placebo group.

Does this mean everyone should use 5 mg for maintenance?

No. The trial shows that 5 mg can be a reasonable maintenance option for some people after a long initial course at 10 mg or 15 mg. It does not identify who will do well on 5 mg before the dose is reduced.

Several factors still matter:

• appetite and food preoccupation at the lower dose
• weight trend and waist change over time
• side effects and treatment burden
• blood glucose and other metabolic markers
• strength, protein intake and body composition
• medication cost and reliable access
• the person's preference and tolerance for regain risk

The right target is not the lowest possible dose. It is the lowest treatment burden that keeps weight, health and daily life acceptably stable.

What the study does not prove

SURMOUNT-MAINTAIN did not test every strategy now discussed online. It did not test gradual step-by-step tapering to zero, dosing every two weeks, restarting only after regain, or using lifestyle support as a substitute for medication. It also did not compare a structured physician-led maintenance programme with routine follow-up.

The study population had already tolerated 60 weeks of tirzepatide and reached 10 mg or 15 mg. People with diabetes were excluded. Its findings should not be applied automatically to someone who stopped early, could not tolerate dose escalation, had a long treatment gap or uses Mounjaro for diabetes.

The trial was funded by Eli Lilly, and several authors were company employees or had industry relationships. This does not invalidate a randomised trial, but it is a reason to keep claims close to the endpoints that were actually studied.

Medication maintenance is not the whole maintenance plan

The trial answers a dose question. It does not answer the whole weight-maintenance question. Long-term care should also protect muscle and function, detect regain early, and make the plan affordable enough to continue.

A stable scale can still conceal loss of strength or an unsustainable routine. A small rise in weight may be acceptable if health, body composition and daily function remain strong. Useful measures may include waist trend, strength, protein intake, activity, sleep, appetite, side effects and relevant laboratory markers.

Related resources: check whether your maintenance plan is ready, read why weight loss is not the same as preserving muscle, or review what is known about restarting after a break.

A practical decision framework

Before changing a Mounjaro dose, agree on four things with the clinician managing treatment:

1. The reason for the change. Is the problem side effects, cost, access, treatment burden or a genuine wish to stop?
2. The maintenance target. Define an acceptable weight range and the health or function markers that matter.
3. The review window. Decide when weight, appetite, side effects and metabolic markers will be reassessed.
4. The response threshold. Decide in advance what would trigger nutrition support, closer follow-up, a dose review or another clinical assessment.

This turns dose reduction into a monitored clinical decision rather than an experiment with no safety net.

Frequently asked questions

The bottom line

SURMOUNT-MAINTAIN moves the discussion beyond a false choice between staying on the highest dose and stopping completely. For some people, reducing Mounjaro to 5 mg may offer a useful middle path. It is not guaranteed to work, and it should be monitored.

Élan Clinic focuses on what happens after weight loss: choosing a maintainable plan, preserving muscle and health, and responding before early regain becomes a larger relapse.