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Weight loss · trial results

Zepbound weight loss results: 12 to 88 weeks

There is no published 12-week Zepbound weight-loss result. The FDA label reports group averages at 72 weeks, while SURMOUNT-4 follows a selected group to 88 weeks.

Source: the current FDA label, SURMOUNT-4 and SURMOUNT-5

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewerReviewed 2026-08-17open the primary sources

Read these results correctly

12 weeks
No study result published
72 weeks
Two FDA-label populations
88 weeks
A selected continuation group
Personal forecast
None of these numbers

The evidence clock

What is known at 12, 36, 72 and 88 weeks

A week on this line can be a dosing marker or a result. Those are not the same thing. The blank result at week 12 is shown on purpose, because no number is more honest than an estimate the trials never published.

  1. Week 0

    Treatment starts

    Protocol

    The label starts at 2.5 mg once weekly. That is a dosing marker, not a measured weight-loss result.

  2. Week 12

    No published 12-week result

    Not published

    Under the earliest label schedule, people are still moving up doses at week 12. The label trials do not publish a 12-week weight result or a monthly rate.

  3. Week 36

    SURMOUNT-4 lead-in ends

    Measured

    −20.9% mean change

    This average describes the people who stayed on treatment, reached 10 or 15 mg and qualified for randomization. It is not an all-starters result.

  4. Week 72

    The FDA-label endpoints

    Measured

    −12.8% to −20.9% across Zepbound arms

    The exact result depends on the dose group and whether people had diabetes. The 2 study groups are shown separately below.

  5. Week 88

    SURMOUNT-4 continuation result

    Measured

    −25.3% continued · −9.9% switched

    These are changes from the original start after 36 weeks of open treatment plus 52 randomized weeks. The switched group received placebo, not a lower Zepbound dose.

The label’s 72-week answer

Diabetes status changes which result belongs in the answer

The FDA label does not print one universal Zepbound result. It prints one trial in adults without type 2 diabetes and another in adults with it. Each percentage is a group average from that named arm, not a result one person should expect.

Adults without type 2 diabetes

NCT04184622 · 2,539 people · 72 weeks

Adults without type 2 diabetes: average weight change and the share who lost at least 20% by week 72
Trial groupAverage changeLost at least 20%
Placebo−3.1%3.1%
Zepbound 5 mg−15.0%30.0%
Zepbound 10 mg−19.5%50.1%
Zepbound 15 mg−20.9%56.7%

Adults with type 2 diabetes

NCT04657003 · 938 people · 72 weeks

Adults with type 2 diabetes: average weight change and the share who lost at least 20% by week 72
Trial groupAverage changeLost at least 20%
Placebo−3.2%1.0%
Zepbound 10 mg−12.8%21.5%
Zepbound 15 mg−14.7%30.8%

SURMOUNT-4 · continuing versus switching

What happened after the first 36 weeks?

Everyone who entered the randomized part had already stayed on Zepbound and reached 10 or 15 mg. They had lost an average −20.9% during the open first 36 weeks. That selection matters: this was not a fresh group starting at week zero.

Continued Zepbound

−25.3%

Average change from the original start at week 88. During the randomized 52 weeks, this group lost another −5.5%.

Switched to placebo

−9.9%

Average change from the original start at week 88. During the randomized 52 weeks, this group changed +14.0% from its week-36 weight.

The switched group received placebo rather than a smaller Zepbound dose. SURMOUNT-4 did not test a taper, and its percentages are changes in body weight—not the share of lost weight regained.

SURMOUNT-5 · one direct comparison

How did tirzepatide compare with semaglutide?

In 751 adults with obesity but without type 2 diabetes, the 72-week group average was −20.2%with tirzepatide and −13.7% with semaglutide. That is a head-to-head trial result, not proof that either drug is right for a particular person.

Compare Wegovy and Zepbound beyond the weight result

The questions people actually ask

What can these results answer?

How much weight did people lose in the first month?

The FDA label does not publish a one-month group mean, and none of the trials on this page publishes a per-month rate. Turning a 72-week average into monthly slices would invent a pattern the studies did not measure.

When do Zepbound results start?

These sources report scheduled group checkpoints, not the first day each person noticed a change. At week 12, people are still moving up the label’s dose steps; it is not a published results endpoint.

Do the 72-week percentages predict an individual result?

No. They are averages for randomized trial groups. Individual results varied, and the two label trials enrolled different populations.

What happens if someone stops?

SURMOUNT-4 measured a switch from Zepbound to placebo after a selected 36-week lead-in. It did not test a taper or write a stopping plan.

Where to read next

5primary sources, each with the day we read it — open the documents used on this page
Zepbound is a registered trademark of Eli Lilly and Company. This page is not written, reviewed or endorsed by Lilly. It reports public label and trial results and does not give medical advice.